Surface polish: batched Minor findings from the native-surfaces final review (#71) (#75)

src/diffViewController.ts

@@ -145,7 +145,13 @@ export class DiffViewController implements vscode.Disposable {
   pin(document: vscode.TextDocument): void {
     if (!this.isDiffable(document)) return;
     const key = this.uriKey(document);
-    if (this.modes.get(key) !== "snapshot") {
+    const mode = this.modes.get(key);
+    if (mode === undefined) {
+      // never established — the document is not being coedited (#71 item 1)
+      void vscode.window.showWarningMessage("Run ✦ Coedit this Document with Claude first.");
+      return;
+    }
+    if (mode !== "snapshot") {
       void vscode.window.showWarningMessage(
         "Cowriting: this document is git-tracked — commit to advance the baseline.",
       );

src/gitBaseline.ts

@@ -119,7 +119,12 @@ export class GitBaselineAdapter implements vscode.Disposable {
         if (pending) clearTimeout(pending);
         pending = setTimeout(() => void repo.status().catch(() => {}), 150);
       });
-      this.disposables.push({ dispose: () => watcher.close() });
+      this.disposables.push({
+        dispose: () => {
+          watcher.close();
+          if (pending) clearTimeout(pending);
+        },
+      });
     } catch {
       // best-effort only — the passive repo.state.onDidChange listener still applies.
     }