chore: align sqlite control plane architecture

- replace default Convex control-plane wording with Rust SQLite control-plane across architecture, AGENTS, Reasonix, and design docs

- retire root Convex functions source and deploy script into recycle while keeping explicit cloud/compat/sync-replica boundaries

- add control-plane migration guard/docs and keep CodeGraph refreshed after the SQLite control-plane cutover

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

@@ -1,6 +1,7 @@
 use crate::app::AppState;
 use crate::context::RequestContext;
 use crate::error::WebError;
+use crate::routes::gateway::default_workspace_name_for_context;
 use crate::routes::web_shell::{
     build_page_aggregate_snapshot, load_file_tree_html, load_sidebar_tree_html,
     load_workspace_shell_projection, render_local_file_tree_html, render_local_sidebar_tree_html,
@@ -30,7 +31,7 @@ pub async fn mindmap_object_shell(
     Path((doc_id, mindmap_id)): Path<(String, String)>,
     Query(query): Query<MindmapShellQuery>,
 ) -> Result<Response, WebError> {
-    let default_workspace_name = format!("{} 的空间", state.config().dev_user_name);
+    let default_workspace_name = default_workspace_name_for_context(&state, &context);
     let source_kind = query.source_kind.as_deref();
     let root_uri = query.root_uri.as_deref();
     let aggregate = build_page_aggregate_snapshot(