feat(desktop): add Vercel static site deployment (PR 0003)

[tokg-venv]

Summary

Implements spec 0003: one-click deployment of a workspace folder of static files to Vercel, driven from the desktop app.

Details

• bun/vercel: VercelTokenStore persists the deploy token to settings/vercel.json inside the bun process (0600 perms, never exposed to the renderer); VercelClient wraps the REST API (create project, upload files, await deployment ready).
• RPC contract (shared/rpc.ts) + handlers (bun/rpc): getVercelStatus, setVercelToken, removeVercelToken, deployToVercel, vercelPreflight.
• Deploy dialog: token setup, folder validation via preflight (index.html presence, size limits), progress states, public-URL result with copy button; errors map to friendly renderer copy.
• Entry points: command palette ("Deploy to Vercel"), page controller, file-tree context menu, account-page connection card.
• i18n: en/zh strings for all new UI.

Test plan

• bun test apps/desktop/src/bun/vercel/ — 18 unit tests for the Vercel client + token store pass.
• bun run typecheck:changed / bun run lint:changed clean.

[tokg-venv]

This PR was auto-closed on 2026-09-13 when its head fork was deleted during a fork-network repair (the fork had been detached from upstream by an earlier ownership transfer, which silently broke PR creation; deleting and re-forking was the fix, but I failed to check for open PRs riding on that fork first — sorry, that was my miss). Re-submitted as #173 from the exact head SHA GitHub retained for this PR: the diff and review state are unchanged.