feat(tree): complete rust family runtime checklist

- add tree shell runtime artifact contracts and page/filetree/picker runtime reducers
- sink tree.subtree.move write operation through Rust and formalize command event plans
- harden file tree search projection contract and route thin-proxy boundaries
- record completed harness tasks and move design docs into process/done

rust/crates/mnote-web/src/routes/tree.rs

@@ -2242,6 +2242,10 @@ fn build_tree_shell_html(
           if (nextExpanded) expanded.add(nodeId);
           else expanded.delete(nodeId);
           postPageExpandChange(nodeId, nextExpanded);
+          if (mode === "page" && usedRustInitialRenderer && patchPageTreeExpansionDom(nodeId)) {
+            focusRowElement(nodeId);
+            return;
+          }
           renderTree();
         };
 
@@ -2410,6 +2414,11 @@ fn build_tree_shell_html(
           }
           focusedNodeId = nodeId;
           postPageFocusChange(nodeId);
+          if (usedRustInitialRenderer) {
+            patchPageTreeActiveDom();
+            focusRowElement(nodeId);
+            return;
+          }
           renderTree();
           focusRowElement(nodeId);
         };
@@ -2460,7 +2469,11 @@ fn build_tree_shell_html(
             if (item?.childCount > 0 && !expanded.has(item.nodeId)) {
               expanded.add(item.nodeId);
               postPageExpandChange(item.nodeId, true);
-              renderTree();
+              if (usedRustInitialRenderer) {
+                patchPageTreeExpansionDom(item.nodeId);
+              } else {
+                renderTree();
+              }
               focusRowElement(item.nodeId);
               return;
             }
@@ -2474,7 +2487,11 @@ fn build_tree_shell_html(
             if (item?.childCount > 0 && expanded.has(item.nodeId)) {
               expanded.delete(item.nodeId);
               postPageExpandChange(item.nodeId, false);
-              renderTree();
+              if (usedRustInitialRenderer) {
+                patchPageTreeExpansionDom(item.nodeId);
+              } else {
+                renderTree();
+              }
               focusRowElement(item.nodeId);
               return;
             }
@@ -2524,12 +2541,13 @@ fn build_tree_shell_html(
           });
         };
 
-        const applyPickerFocusByItemKey = (pickerItemKey) => {
+        const applyPickerFocusByItemKey = (pickerItemKey, options = {}) => {
           if (mode !== "picker") return;
           const result = computePickerStateActionResult({
             kind: "focus",
             itemKey: pickerItemKey,
           });
+          const shouldFocusDom = options.focusDom === true;
           const nextPickerItemKey = result.nextItemKey || "";
           const nextDocumentId =
             nextPickerItemKey && nextPickerItemKey !== "__root__"
@@ -2541,11 +2559,11 @@ fn build_tree_shell_html(
           focusedNodeId = nextDocumentId || "";
           if (usedRustInitialRenderer) {
             patchPickerActiveDom();
-            focusPickerRowElement(nextPickerItemKey);
+            if (shouldFocusDom) focusPickerRowElement(nextPickerItemKey);
           } else {
             renderTree();
           }
-          if (nextDocumentId) {
+          if (shouldFocusDom && nextDocumentId) {
             focusRowElement(nextDocumentId);
           }
           postPickerFocusChange(nextPickerItemKey || null);
@@ -2567,6 +2585,27 @@ fn build_tree_shell_html(
           return result;
         };
 
+        const postPickerPickResultToHost = (result) => {
+          if (mode !== "picker" || !result) return;
+          if (result.pickedRoot) {
+            setLastAction("已选择根目录");
+            postToHost("tree.pick.root", {
+              documentId: null,
+              target: { documentId: null },
+              payload: { documentId: null },
+            });
+            return;
+          }
+          if (result.pickedDocumentId) {
+            postToHost("tree.pick", {
+              documentId: result.pickedDocumentId,
+              itemKey: result.nextItemKey || result.pickedDocumentId,
+              target: { documentId: result.pickedDocumentId },
+              payload: { documentId: result.pickedDocumentId },
+            });
+          }
+        };
+
         const handlePickerCommand = (command) => {
           if (mode !== "picker") return;
 
@@ -2576,19 +2615,7 @@ fn build_tree_shell_html(
           }
 
           if (normalizedCommand === "pick") {
-            const result = applyPickerStateAction({ kind: "pick" });
-            if (result.pickedRoot) {
-              setLastAction("已选择根目录");
-              postToHost("tree.pick.root", {
-                documentId: null,
-                target: { documentId: null },
-                payload: { documentId: null },
-              });
-              return;
-            }
-            if (result.pickedDocumentId) {
-              handleNavigate(result.pickedDocumentId);
-            }
+            postPickerPickResultToHost(applyPickerStateAction({ kind: "pick" }));
             return;
           }
 
@@ -2947,7 +2974,10 @@ fn build_tree_shell_html(
             element.addEventListener("click", (event) => {
               event.stopPropagation();
               const action = normalizeText(element.dataset.rustAction);
-              if (action === "open") {
+              if (action === "toggle") {
+                event.preventDefault();
+                toggleExpand(item.nodeId);
+              } else if (action === "open") {
                 handleNavigate(item.nodeId);
               } else if (action === "create") {
                 void handleCreate(item.nodeId);
@@ -2961,6 +2991,72 @@ fn build_tree_shell_html(
           });
         };
 
+        const patchPageTreeActiveDom = () => {
+          if (mode !== "page") return;
+          appElement.querySelectorAll('[data-rust-rendered-row="page"]').forEach((row) => {
+            if (!(row instanceof HTMLElement)) return;
+            const nodeId = normalizeText(row.dataset.nodeId);
+            const isFocused = nodeId === focusedNodeId;
+            row.dataset.active = String(nodeId === currentActiveDocumentId);
+            row.dataset.focused = String(isFocused);
+            row.tabIndex = isFocused ? 0 : -1;
+            row.dataset.dropFeedback = String(activePageDropNodeId === nodeId);
+          });
+        };
+
+        const patchPageTreeExpansionDom = (nodeId) => {
+          if (mode !== "page") return false;
+          const normalizedNodeId = normalizeText(nodeId);
+          if (!normalizedNodeId) return false;
+          const item = itemById.get(normalizedNodeId);
+          if (!item) return false;
+          const nodeElement = appElement.querySelector(
+            `.tree-node[data-node-id="${CSS.escape(normalizedNodeId)}"]`,
+          );
+          if (!(nodeElement instanceof HTMLElement)) return false;
+          const row = nodeElement.querySelector(
+            `:scope > .tree-row[data-node-id="${CSS.escape(normalizedNodeId)}"]`,
+          );
+          const children = getSiblings(normalizedNodeId);
+          const hasChildren = item.childCount > 0 && children.length > 0;
+          const isExpanded = hasChildren && expanded.has(normalizedNodeId);
+          if (row instanceof HTMLElement) {
+            row.setAttribute("aria-expanded", hasChildren ? String(isExpanded) : "false");
+            const toggleButton = row.querySelector('[data-testid="tree-node-toggle"]');
+            if (toggleButton instanceof HTMLButtonElement) {
+              toggleButton.textContent = isExpanded ? "▾" : "▸";
+              toggleButton.setAttribute(
+                "aria-label",
+                `${isExpanded ? "折叠" : "展开"} ${item.title}`,
+              );
+            }
+          }
+          if (!hasChildren) {
+            patchPageTreeActiveDom();
+            return true;
+          }
+          let childrenList = Array.from(nodeElement.children).find(
+            (child) => child instanceof HTMLElement && child.classList.contains("tree-children"),
+          );
+          if (isExpanded) {
+            if (!(childrenList instanceof HTMLElement)) {
+              childrenList = document.createElement("ul");
+              childrenList.className = "tree-children";
+              children.forEach((child) => {
+                childrenList.appendChild(renderNode(child));
+              });
+              nodeElement.appendChild(childrenList);
+            }
+            childrenList.hidden = false;
+            childrenList.style.display = "";
+          } else if (childrenList instanceof HTMLElement) {
+            childrenList.hidden = true;
+            childrenList.style.display = "none";
+          }
+          patchPageTreeActiveDom();
+          return true;
+        };
+
         const hydrateInitialPageTree = () => {
           if (mode !== "page") return false;
           const root = appElement.querySelector('[data-rust-page-renderer="initial_v1"]');
@@ -3210,12 +3306,8 @@ fn build_tree_shell_html(
           if (!(row instanceof HTMLElement)) return;
           row.dataset.focused = String(resolvePickerRootFocused());
           row.addEventListener("click", () => {
-            setLastAction("已选择根目录");
-            postToHost("tree.pick.root", {
-              documentId: null,
-              target: { documentId: null },
-              payload: { documentId: null },
-            });
+            applyPickerFocusByItemKey("__root__", { focusDom: true });
+            postPickerPickResultToHost(applyPickerStateAction({ kind: "pick" }));
           });
         };
 
@@ -3228,7 +3320,8 @@ fn build_tree_shell_html(
             (!currentActivePickerItemKey && currentActiveDocumentId === item.nodeId),
           );
           row.addEventListener("click", () => {
-            handleNavigate(item.nodeId);
+            applyPickerFocusByItemKey(item.nodeId, { focusDom: true });
+            postPickerPickResultToHost(applyPickerStateAction({ kind: "pick" }));
           });
         };
 
@@ -3447,7 +3540,14 @@ fn build_tree_shell_html(
           linkButton.className = "tree-link";
           linkButton.setAttribute("data-testid", "tree-node-open");
           linkButton.setAttribute("aria-label", `打开 ${item.title}`);
-          linkButton.addEventListener("click", () => handleNavigate(item.nodeId));
+          linkButton.addEventListener("click", () => {
+            if (mode === "picker") {
+              applyPickerFocusByItemKey(item.nodeId, { focusDom: true });
+              postPickerPickResultToHost(applyPickerStateAction({ kind: "pick" }));
+              return;
+            }
+            handleNavigate(item.nodeId);
+          });
 
           const titleElement = document.createElement("span");
           titleElement.className = "tree-link-title";
@@ -3812,13 +3912,10 @@ fn build_tree_shell_html(
             rootButton.className = "tree-row";
             rootButton.setAttribute("data-testid", "tree-picker-root");
             rootButton.dataset.focused = String(resolvePickerRootFocused());
+            rootButton.tabIndex = resolvePickerRootFocused() ? 0 : -1;
             rootButton.addEventListener("click", () => {
-              setLastAction("已选择根目录");
-              postToHost("tree.pick.root", {
-                documentId: null,
-                target: { documentId: null },
-                payload: { documentId: null },
-              });
+              applyPickerFocusByItemKey("__root__", { focusDom: true });
+              postPickerPickResultToHost(applyPickerStateAction({ kind: "pick" }));
             });
 
             const spacer = document.createElement("div");
@@ -3903,7 +4000,6 @@ fn build_tree_shell_html(
           focusedNodeId = resolveFocusedNodeIdFromHostState();
           if (mode === "picker" && usedRustInitialRenderer) {
             patchPickerActiveDom();
-            focusPickerRowElement(currentActivePickerItemKey);
             return;
           }
           renderTree();
@@ -4345,8 +4441,12 @@ mod tests {
         assert!(html.contains("tree.shell.state.patch"));
         assert!(html.contains("\"contractName\":\"rust_page_focus_keyboard_reducer_v1\""));
         assert!(html.contains("applyPageKeyboardAction"));
+        assert!(html.contains("patchPageTreeActiveDom"));
+        assert!(html.contains("patchPageTreeExpansionDom"));
         assert!(html.contains("data-rust-page-renderer=\"initial_v1\""));
         assert!(html.contains("data-rust-rendered-row=\"page\""));
+        assert!(html.contains("data-rust-action=\"toggle\""));
+        assert!(html.contains("data-testid=\"tree-node-toggle\""));
         assert!(html.contains("hydrateInitialPageTree"));
         assert!(html.contains("const usedRustInitialPageRenderer = hydrateInitialPageTree();"));
         assert!(html.contains("application/x-mnote-page-tree-node"));
@@ -4382,8 +4482,14 @@ mod tests {
         assert!(html.contains("tree.picker.focus.changed"));
         assert!(html.contains("\"contractName\":\"rust_picker_state_reducer_v1\""));
         assert!(html.contains("applyPickerStateAction"));
+        assert!(html.contains("postPickerPickResultToHost"));
+        assert!(html.contains("applyPickerFocusByItemKey(\"__root__\", { focusDom: true })"));
+        assert!(html.contains("applyPickerFocusByItemKey(item.nodeId, { focusDom: true })"));
+        assert!(html.contains("const shouldFocusDom = options.focusDom === true"));
+        assert!(html.contains("if (shouldFocusDom) focusPickerRowElement"));
         assert!(html.contains("patchPickerActiveDom"));
         assert!(html.contains("hydrateInitialPickerTree"));
+        assert!(html.contains("tabindex=\""));
         assert!(html.contains("const usedRustInitialRenderer = hydrateInitialRenderer();"));
         assert!(html.contains("__MNOTE_TREE_SHELL_OVERRIDE__"));
     }
@@ -4442,6 +4548,9 @@ mod tests {
         assert!(filetree_html.contains("\"filetreeSelection\""));
         assert!(filetree_html.contains("\"selectedRowIds\""));
         assert!(filetree_html.contains("\"commandDispatcher\""));
+        assert!(filetree_html.contains("\"runtimeArtifact\""));
+        assert!(filetree_html.contains("\"contractName\":\"rust_tree_shell_runtime_artifact_v1\""));
+        assert!(filetree_html.contains("\"outputChannels\":[\"commandDispatchEvent\",\"domPatch\",\"intentEvent\"]"));
 
         let picker_response = app()
             .oneshot(
@@ -4460,6 +4569,8 @@ mod tests {
         assert!(picker_html.contains("\"mode\":\"picker\""));
         assert!(picker_html.contains("\"activePickerItem\":\"page_child\""));
         assert!(picker_html.contains("\"excludedPickerIds\":[\"page_root\"]"));
+        assert!(picker_html.contains("\"runtimeArtifact\""));
+        assert!(picker_html.contains("\"contractName\":\"rust_tree_shell_runtime_artifact_v1\""));
     }
 
     #[tokio::test]

rust/crates/mnote-web/src/tree_shell/mod.rs

@@ -3,12 +3,15 @@ pub mod drag_drop_state;
 pub mod dispatcher;
 pub mod expansion_state;
 pub mod filetree_renderer;
+pub mod filetree_runtime;
 pub mod filetree_selection;
 pub mod focus_state;
 pub mod keyboard_state;
 pub mod loader;
 pub mod page_renderer;
+pub mod page_runtime;
 pub mod picker_renderer;
+pub mod picker_runtime;
 pub mod picker_state;
 pub mod protocol;
 pub mod renderer_input;

rust/crates/mnote-web/src/tree_shell/page_renderer.rs

@@ -78,8 +78,19 @@ fn render_page_row(
             .find(|source| source.node_id == row.node_id)
             .map(|source| source.expanded)
             .unwrap_or(false);
+        let toggle_html = if row.expandable {
+            format!(
+                r#"<button type="button" class="tree-toggle" data-testid="tree-node-toggle" data-rust-action="toggle" data-node-id="{node_id}" aria-label="{label} {title}">{marker}</button>"#,
+                node_id = escape_html(&row.node_id),
+                label = if expanded { "折叠" } else { "展开" },
+                title = escape_html(&row.title),
+                marker = if expanded { "▾" } else { "▸" },
+            )
+        } else {
+            r#"<span class="tree-spacer" aria-hidden="true"></span>"#.to_string()
+        };
         html.push_str(&format!(
-            r#"<li class="tree-node" data-node-id="{node_id}"><div class="tree-row" role="treeitem" aria-level="{aria_level}" aria-expanded="{expanded_attr}" data-rust-rendered-row="page" data-testid="{test_id}" data-node-id="{node_id}" data-shell-mode="page" data-active="{active}" data-focused="{focused}" data-draggable="true" draggable="true" tabindex="{tab_index}"><span class="tree-spacer" aria-hidden="true"></span><span class="tree-kind-badge" data-kind="page" aria-hidden="true"></span><button type="button" class="tree-link" data-testid="tree-node-open" data-rust-action="open" data-node-id="{node_id}"><span class="tree-link-title">{title}</span></button><div class="tree-actions"><button type="button" class="tree-action" data-testid="tree-action-create" data-rust-action="create" data-node-id="{node_id}" aria-label="新建子页面">+</button><button type="button" class="tree-action" data-testid="tree-action-rename" data-rust-action="rename" data-node-id="{node_id}" aria-label="重命名">✎</button><button type="button" class="tree-action" data-testid="tree-action-menu" data-rust-action="menu" data-node-id="{node_id}" aria-label="更多操作">…</button></div></div>"#,
+            r#"<li class="tree-node" data-node-id="{node_id}"><div class="tree-row" role="treeitem" aria-level="{aria_level}" aria-expanded="{expanded_attr}" data-rust-rendered-row="page" data-testid="{test_id}" data-node-id="{node_id}" data-shell-mode="page" data-active="{active}" data-focused="{focused}" data-draggable="true" draggable="true" tabindex="{tab_index}">{toggle_html}<span class="tree-kind-badge" data-kind="page" aria-hidden="true"></span><button type="button" class="tree-link" data-testid="tree-node-open" data-rust-action="open" data-node-id="{node_id}"><span class="tree-link-title">{title}</span></button><div class="tree-actions"><button type="button" class="tree-action" data-testid="tree-action-create" data-rust-action="create" data-node-id="{node_id}" aria-label="新建子页面">+</button><button type="button" class="tree-action" data-testid="tree-action-rename" data-rust-action="rename" data-node-id="{node_id}" aria-label="重命名">✎</button><button type="button" class="tree-action" data-testid="tree-action-menu" data-rust-action="menu" data-node-id="{node_id}" aria-label="更多操作">…</button></div></div>"#,
             node_id = escape_html(&row.node_id),
             aria_level = row.depth + 1,
             expanded_attr = if row.expandable && expanded { "true" } else { "false" },
@@ -87,6 +98,7 @@ fn render_page_row(
             active = active,
             focused = focused,
             tab_index = if focused { "0" } else { "-1" },
+            toggle_html = toggle_html,
             title = escape_html(&row.title),
         ));
         if row.expandable && expanded {
@@ -206,6 +218,8 @@ mod tests {
         assert!(html.contains("data-rust-rendered-row=\"page\""));
         assert!(html.contains("data-shell-mode=\"page\""));
         assert!(html.contains("data-rust-action=\"open\""));
+        assert!(html.contains("data-rust-action=\"toggle\""));
+        assert!(html.contains("data-testid=\"tree-node-toggle\""));
         assert!(html.contains("data-rust-action=\"create\""));
         assert!(html.contains("draggable=\"true\""));
         assert!(html.contains("tree-children"));

rust/crates/mnote-web/src/tree_shell/picker_renderer.rs

@@ -52,11 +52,12 @@ fn render_picker_row(
     children_by_parent: &BTreeMap<Option<String>, Vec<PickerRenderRow>>,
 ) {
     html.push_str(&format!(
-        r#"<li class="tree-node" data-node-id="{node_id}"><button type="button" class="tree-row" role="treeitem" aria-level="{aria_level}" aria-expanded="{expanded_attr}" data-rust-rendered-row="picker" data-testid="tree-picker-row" data-node-id="{node_id}" data-shell-mode="picker" data-focused="{active}" data-rust-action="pick"><span class="tree-spacer" aria-hidden="true"></span><span class="tree-kind-badge" data-kind="page" aria-hidden="true"></span><span class="tree-link"><span class="tree-link-title">{title}</span></span></button>"#,
+        r#"<li class="tree-node" data-node-id="{node_id}"><button type="button" class="tree-row" role="treeitem" aria-level="{aria_level}" aria-expanded="{expanded_attr}" data-rust-rendered-row="picker" data-testid="tree-picker-row" data-node-id="{node_id}" data-shell-mode="picker" data-focused="{active}" data-rust-action="pick" tabindex="{tabindex}"><span class="tree-spacer" aria-hidden="true"></span><span class="tree-kind-badge" data-kind="page" aria-hidden="true"></span><span class="tree-link"><span class="tree-link-title">{title}</span></span></button>"#,
         node_id = escape_html(&row.node_id),
         aria_level = row.depth + 1,
         expanded_attr = if row.expandable && row.expanded { "true" } else { "false" },
         active = row.active,
+        tabindex = if row.active { "0" } else { "-1" },
         title = escape_html(&row.title),
     ));
     if row.expandable && row.expanded {
@@ -77,8 +78,9 @@ pub fn render_initial_picker_html(input: &PickerInitialRenderInput) -> String {
     );
     if input.allow_root_pick {
         html.push_str(&format!(
-            r#"<li class="tree-node" data-node-id="__root__"><button type="button" class="tree-row" data-testid="tree-picker-root" data-rust-rendered-row="picker-root" data-rust-action="pick-root" data-focused="{focused}"><span class="tree-spacer" aria-hidden="true"></span><span class="tree-link"><span class="tree-link-title">根目录</span></span></button></li>"#,
+            r#"<li class="tree-node" data-node-id="__root__"><button type="button" class="tree-row" data-testid="tree-picker-root" data-rust-rendered-row="picker-root" data-rust-action="pick-root" data-focused="{focused}" tabindex="{tabindex}"><span class="tree-spacer" aria-hidden="true"></span><span class="tree-link"><span class="tree-link-title">根目录</span></span></button></li>"#,
             focused = input.root_active,
+            tabindex = if input.root_active { "0" } else { "-1" },
         ));
     }
 
@@ -180,6 +182,14 @@ mod tests {
                 expandable: false,
                 expanded: false,
                 active: true,
+            }, PickerRenderRow {
+                node_id: "page_other".into(),
+                parent_node_id: None,
+                title: "其他页面".into(),
+                depth: 0,
+                expandable: false,
+                expanded: false,
+                active: false,
             }],
         });
 
@@ -190,5 +200,7 @@ mod tests {
         assert!(html.contains("data-testid=\"tree-picker-row\""));
         assert!(html.contains("首页 &lt;安全&gt;"));
         assert!(html.contains("data-focused=\"true\""));
+        assert!(html.contains("tabindex=\"0\""));
+        assert!(html.contains("tabindex=\"-1\""));
     }
 }

rust/crates/mnote-web/src/tree_shell/renderer_input.rs

@@ -26,6 +26,7 @@ pub struct TreeShellRendererInput {
     pub excluded_picker_ids: BTreeSet<String>,
     pub picker_state_reducer: Option<PickerStateReducerContract>,
     pub command_dispatcher: TreeShellCommandDispatcher,
+    pub runtime_artifact: TreeShellRuntimeArtifactBoundary,
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Serialize)]
@@ -35,6 +36,41 @@ pub struct TreeShellCommandDispatcher {
     pub command_names: BTreeSet<String>,
 }
 
+#[derive(Debug, Clone, PartialEq, Eq, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct TreeShellRuntimeArtifactBoundary {
+    pub contract_name: &'static str,
+    pub input_fields: BTreeSet<&'static str>,
+    pub output_channels: BTreeSet<&'static str>,
+    pub event_kinds: BTreeSet<&'static str>,
+}
+
+impl Default for TreeShellRuntimeArtifactBoundary {
+    fn default() -> Self {
+        Self {
+            contract_name: "rust_tree_shell_runtime_artifact_v1",
+            input_fields: BTreeSet::from([
+                "rendererInput",
+                "projectionItems",
+                "expandedIds",
+                "selectedRowIds",
+                "activePickerItem",
+                "focusedId",
+            ]),
+            output_channels: BTreeSet::from(["domPatch", "intentEvent", "commandDispatchEvent"]),
+            event_kinds: BTreeSet::from([
+                "focus",
+                "keyboard",
+                "expandCollapse",
+                "selection",
+                "contextMenu",
+                "dragDrop",
+                "pick",
+            ]),
+        }
+    }
+}
+
 impl TreeShellRendererInput {
     pub fn page(input: PageTreeRendererInput) -> Self {
         Self {
@@ -49,6 +85,7 @@ impl TreeShellRendererInput {
             excluded_picker_ids: BTreeSet::new(),
             picker_state_reducer: None,
             command_dispatcher: input.command_dispatcher,
+            runtime_artifact: TreeShellRuntimeArtifactBoundary::default(),
         }
     }
 
@@ -65,6 +102,7 @@ impl TreeShellRendererInput {
             excluded_picker_ids: BTreeSet::new(),
             picker_state_reducer: None,
             command_dispatcher: input.command_dispatcher,
+            runtime_artifact: TreeShellRuntimeArtifactBoundary::default(),
         }
     }
 
@@ -81,6 +119,7 @@ impl TreeShellRendererInput {
             excluded_picker_ids: input.excluded_picker_ids,
             picker_state_reducer: Some(PickerStateReducerContract::default()),
             command_dispatcher: input.command_dispatcher,
+            runtime_artifact: TreeShellRuntimeArtifactBoundary::default(),
         }
     }
 }
@@ -113,8 +152,8 @@ pub struct PickerRendererInput {
 #[cfg(test)]
 mod tests {
     use super::{
-        FileTreeRendererInput, PageTreeRendererInput, PickerRendererInput, TreeShellCommandDispatcher,
-        TreeShellRendererInput, TreeShellRendererMode,
+        FileTreeRendererInput, PageTreeRendererInput, PickerRendererInput,
+        TreeShellCommandDispatcher, TreeShellRendererInput, TreeShellRendererMode,
     };
     use crate::tree_shell::filetree_selection::FileTreeSelectionState;
     use std::collections::BTreeSet;
@@ -158,7 +197,10 @@ mod tests {
         });
         assert_eq!(filetree.mode, TreeShellRendererMode::FileTree);
         assert_eq!(filetree.focused_id.as_deref(), Some("asset:a"));
-        assert!(filetree.filetree_selection.selected_row_ids.contains("asset:a"));
+        assert!(filetree
+            .filetree_selection
+            .selected_row_ids
+            .contains("asset:a"));
         assert!(filetree.page_focus_keyboard_reducer.is_none());
         assert_eq!(
             filetree
@@ -188,4 +230,36 @@ mod tests {
             Some("rust_picker_state_reducer_v1")
         );
     }
+
+    #[test]
+    fn tree_shell_renderer_input_exposes_runtime_artifact_boundary() {
+        let page = TreeShellRendererInput::page(PageTreeRendererInput {
+            projection_item_ids: vec!["doc:root".into()],
+            expanded_ids: set(&["doc:root"]),
+            focused_id: Some("doc:root".into()),
+            command_dispatcher: dispatcher(),
+        });
+
+        let artifact = page.runtime_artifact;
+        assert_eq!(
+            artifact.contract_name,
+            "rust_tree_shell_runtime_artifact_v1"
+        );
+        assert!(artifact.input_fields.contains("rendererInput"));
+        assert!(artifact.input_fields.contains("projectionItems"));
+        assert!(artifact.input_fields.contains("expandedIds"));
+        assert!(artifact.input_fields.contains("selectedRowIds"));
+        assert!(artifact.input_fields.contains("activePickerItem"));
+        assert!(artifact.input_fields.contains("focusedId"));
+        assert!(artifact.output_channels.contains("domPatch"));
+        assert!(artifact.output_channels.contains("intentEvent"));
+        assert!(artifact.output_channels.contains("commandDispatchEvent"));
+        assert!(artifact.event_kinds.contains("focus"));
+        assert!(artifact.event_kinds.contains("keyboard"));
+        assert!(artifact.event_kinds.contains("expandCollapse"));
+        assert!(artifact.event_kinds.contains("selection"));
+        assert!(artifact.event_kinds.contains("contextMenu"));
+        assert!(artifact.event_kinds.contains("dragDrop"));
+        assert!(artifact.event_kinds.contains("pick"));
+    }
 }