feat: gate every surface on CoeditingRegistry (INV-10) — commenting ranges re-assigned on gate change (spec §6.4 v0.2.1)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/trackChangesPreview.ts

@@ -19,6 +19,10 @@ import { isAuthorable } from "./workspacePath";
 import type { EditTurnResult, RunEditTurnOptions } from "./liveTurn";
 import type { LiveProgressUi } from "./liveProgressUi";
 import { promptEditInstruction } from "./editInstructionInput";
+import type { CoeditingRegistry } from "./coeditingRegistry";
+
+/** The exact warning copy for every gated edit gesture (INV-10). */
+const NOT_COEDITING_WARNING = "Run ✦ Coedit this Document with Claude first.";
 
 /**
  * F11: a host edit turn (selection/document text + instruction → rewrite).
@@ -83,6 +87,7 @@ export class TrackChangesPreviewController implements vscode.Disposable {
     private readonly attribution: AttributionController,
     private readonly proposals: ProposalController,
     private readonly liveProgressUi: LiveProgressUi,
+    private readonly registry: CoeditingRegistry,
   ) {
     this.disposables.push(
       // F11 (SLICE-5): the editor/title gateway passes the tab's resource Uri;
@@ -247,6 +252,13 @@ export class TrackChangesPreviewController implements vscode.Disposable {
    * the result as F4 proposal(s). UI wrapper around `runEditAndPropose`.
    */
   private async askClaude(document: vscode.TextDocument, target: EditTarget): Promise<void> {
+    // INV-10: the choke point for BOTH the editDocument command and the webview's
+    // askClaude toolbar intent (either scope) — a non-entered doc gets the warning,
+    // not a turn.
+    if (!this.registry.isCoediting(document.uri)) {
+      void vscode.window.showWarningMessage(NOT_COEDITING_WARNING);
+      return;
+    }
     // Both scopes use the same multi-line split-below webview box; only the header
     // (and the downstream proposal logic) differs. For a selection the document
     // above keeps the selection highlighted while the box is open.