fix: harden and de-slop the merged contribution batch

Follow-ups promised on merge, plus review findings on the batch itself:

- chat: task-tool output now respects the 512KiB render cap; quick-open
  icon is visible at rest on coarse pointers and reachable by keyboard
  (row keydown no longer swallows inner-button Enter/Space); composer
  inline-code decoration drops the metric-shifting padding; a btw fork
  send carries only the boundary instruction, never the promotion notice
- sync: cascade revert/unrevert aborts busy descendants, busy state is
  read from every child store at the moment of use; rule 9 documents
  redo clearing all descendant revert markers
- electron: renderer recovery keeps memory-eviction (a valid
  render-process-gone reason) and both windows share one
  attachRendererRecovery helper
- vscode: process registry is a thin re-export of the web module
  (provider-env-aliases precedent) with ordered register/unregister
  writes and an awaited close
- server/cli: managed-process registry takes injectable deps (fixes the
  unreaped-orphans ReferenceError), corrupt settings errors name the
  file, getWorktrees test restores console.warn
- tests: module-mock harnesses removed (AgentsSidebar, SettingsView
  mobile focus — behaviors stay live but uncovered, accepted trade),
  QuestionMarkdown asserts rendered DOM
- i18n: German gains the debug-panel request keys, Japanese/German drop
  removed worktree keys, Ukrainian unit spacing fixed
- changelog: Copilot AI Credits entries (main + VS Code)

packages/web/bin/lib/cli-settings-accessors.js

@@ -40,9 +40,17 @@ export const createSettingsAccessors = ({ fsPromises, path, dataDir, settingsFil
       }
       throw error;
     }
-    const parsed = JSON.parse(raw);
+    const corruptSettingsError = (cause) =>
+      new Error(`Settings file is corrupt or unreadable: ${settingsPath} (fix or remove it, then retry)`, { cause });
+
+    let parsed;
+    try {
+      parsed = JSON.parse(raw);
+    } catch (error) {
+      throw corruptSettingsError(error);
+    }
     if (!parsed || typeof parsed !== 'object') {
-      throw new Error('Settings file is malformed (non-object payload)');
+      throw corruptSettingsError(new Error('non-object payload'));
     }
     return parsed;
   };

packages/web/bin/lib/cli-settings-accessors.test.js

@@ -144,7 +144,16 @@ describe('cli settings accessors', () => {
     await withTempDir(async (dir) => {
       const accessors = makeAccessors(dir);
       fs.writeFileSync(path.join(dir, 'settings.json'), '"just a string"');
-      await expect(accessors.readSettingsStrict()).rejects.toThrow(/non-object payload/);
+      await expect(accessors.readSettingsStrict()).rejects.toThrow(/corrupt or unreadable/);
+    });
+  });
+
+  it('names the settings file in the strict read failure', async () => {
+    await withTempDir(async (dir) => {
+      const accessors = makeAccessors(dir);
+      const filePath = path.join(dir, 'settings.json');
+      fs.writeFileSync(filePath, '{"unfinished": "trunc');
+      await expect(accessors.readSettingsStrict()).rejects.toThrow(filePath);
     });
   });