feat: continue tree rust family cutover

- add rust renderer/state-family scaffolds and inline compat host thinning for page tree, file tree, and picker
- route tree/filetree preflight, file projection, resource artifact, and stream delta contracts through rust plans
- preserve canonical move-order validation, file-tree search projection, and related frontend/runtime regression coverage

rust/crates/core-protocol/src/kernel.rs

@@ -212,6 +212,8 @@ pub struct KernelProjectionFilter {
     pub node_types: Vec<KernelNodeType>,
     #[serde(default)]
     pub edge_types: Vec<KernelEdgeType>,
+    pub query: Option<String>,
+    pub max_results: Option<usize>,
     #[serde(default)]
     pub include_deleted: bool,
 }
@@ -526,6 +528,8 @@ mod tests {
             filters: KernelProjectionFilter {
                 node_types: vec![KernelNodeType::Page, KernelNodeType::Folder],
                 edge_types: vec![KernelEdgeType::ParentOf],
+                query: Some("预算".into()),
+                max_results: Some(20),
                 include_deleted: false,
             },
             include_content: false,
@@ -535,6 +539,8 @@ mod tests {
         let value = serde_json::to_value(&request).expect("request 应可序列化");
         assert_eq!(value["projection"], json!("sidebar_tree"));
         assert_eq!(value["subtree"]["rootNodeId"], json!("page_root"));
+        assert_eq!(value["filters"]["query"], json!("预算"));
+        assert_eq!(value["filters"]["maxResults"], json!(20));
 
         let decoded: KernelProjectionRequest =
             serde_json::from_value(value).expect("request 应可反序列化");