feat(twitter): add switch-account command with --list and @handle modes

[Semonxue]

Adds opencli twitter switch-account for the X account-switcher menu:

• opencli twitter switch-account --list enumerates every account in the switcher, marking the active one.
• opencli twitter switch-account @handle switches into the named account by clicking the matching aria-label="Switch to @handle" button. If handle already matches the active account, returns status: already_current.

isCurrent is detected from the menu's DOM: the current account renders as <li data-testid="UserCell"> (no "Switch to" button), while the other accounts are <button data-testid="UserCell" aria-label="Switch to @xxx">. The trigger avatar was unreliable for this because X caches the previous active account there until a full page reload.

After clicking the switch button, the page is reloaded so the Playwright session syncs to the new account before the next call.

Tests

• npx vitest run --project adapter clis/twitter/switch-account.test.js — 15 / 15 pass
• npm run test:adapter — 382 files / 3780 tests pass
• npm run typecheck — clean
• npm run build — clean, cli-manifest.json regenerates

Live verify

$ node dist/src/main.js twitter switch-account --list
- status: listed
  handle: 2nd_ai50196
  is_current: true
  message: Current account @2nd_ai50196
- ...

$ node dist/src/main.js twitter switch-account @semonxue
- status: switched
  handle: '@semonxue'
  is_current: true
  message: Switched to @semonxue

$ node dist/src/main.js twitter switch-account @semonxue   # already there
- status: already_current
  handle: '@semonxue'
  is_current: true
  message: '@semonxue is already the current account.'

Files

• clis/twitter/switch-account.js — new
• clis/twitter/switch-account.test.js — new, 15 unit tests covering argument routing, readAccountMenu, registration, --list mode, and switch-mode error paths (auth required, malformed handle, target not in menu, already current, switched)
• CHANGELOG.md — ## Unreleased Features entry