feat(f9): preview gains authorship mode + attribution dep + setMode wiring

Per-panel mode (default changes); refresh branches to renderAuthorship reading
AttributionController.spansFor; webview setMode message; extension.ts reorders the
F7 controller after attribution. getMode/setMode test seams.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/extension.ts

@@ -70,16 +70,6 @@ export function activate(context: vscode.ExtensionContext): CowritingApi | undef
   // still works — PUC-5.
   const globalSidecarStore = new GlobalSidecarStore(baselineStorageDir ?? "");
 
-  // --- F7: rendered track-changes preview (Feature #21) — workspace-INDEPENDENT ---
-  // Like F6, F7 works on any markdown doc (incl. untitled / out-of-folder), so it
-  // is constructed regardless of an open folder and its command is always live.
-  // It reuses the F6 baseline (INV-20) and adds no persistence.
-  const trackChangesPreviewController = new TrackChangesPreviewController(
-    diffViewController,
-    context.extensionUri,
-  );
-  context.subscriptions.push(trackChangesPreviewController);
-
   // --- F8: authoring on ANY document (in-folder, out-of-folder, untitled) ---
   // The router routes per-document: in-workspace file: → the committable repo
   // `.threads/` sidecar (CoauthorStore, INV-2); out-of-folder file: + untitled:
@@ -99,6 +89,17 @@ export function activate(context: vscode.ExtensionContext): CowritingApi | undef
   const attributionController = new AttributionController(sidecarRouter, root, versionGuard);
   context.subscriptions.push(attributionController);
 
+  // --- F7: rendered track-changes preview (Feature #21) + F9 authorship mode ---
+  // Workspace-INDEPENDENT (works on any markdown doc, reuses the F6 baseline,
+  // INV-20). Constructed AFTER attribution so F9's authorship view can read F3
+  // spans (AttributionController.spansFor).
+  const trackChangesPreviewController = new TrackChangesPreviewController(
+    diffViewController,
+    context.extensionUri,
+    attributionController,
+  );
+  context.subscriptions.push(trackChangesPreviewController);
+
   // --- F4: propose/accept (Feature #12) ---
   const proposalController = new ProposalController(sidecarRouter, attributionController, root, versionGuard);
   context.subscriptions.push(proposalController);