update download url

Fix 5 issues with the WebUI settings pages:

1. About page links: use window.open in web mode instead of
   shell.openExternal which calls xdg-open on the server

2. System page directories: fix WebSocket adapter to inject
   __webUiUserId into the bridge protocol inner data field.
   The @office-ai/platform bridge wraps payloads as {id, data}
   and providers only receive the inner data — userId was being
   lost at the outer wrapper level.

3. API Keys infinite spinner: same root cause as #2 — providers
   threw 'Authentication required' because __webUiUserId was
   never reaching them through the bridge protocol.

4. Theme quick toggle: add light/dark mode toggle with Sun/Moon
   icons to the user dropdown menu in the sidebar.

5. Claude YOLO toggle: hide behind ALLOW_CLAUDE_YOLO env var
   (default: false). Exposed through branding config IPC so the
   renderer can conditionally render the toggle.

- CRITICAL: use finally block in sendChannelMessage to always release
  cronBusyGuard, preventing permanent busy state when gateway does not
  emit a finish event
- HIGH: replace console.log with console.debug for auth and session key
  logs to avoid polluting production logs
- MEDIUM: move db/dbResult into try block in ChannelMessageService for
  better readability and consistent error handling

Note: the task id vs conversation_id concern (review issue #2) is not
applicable — in WorkerManage, tasks are keyed by conversation.id, so
listTasks().id is always the conversation_id.

…prompt iOfficeAI#2