Vibe projects, step 1: files behind checkpoints, Undo AI change, Versions

[AVADSA25]

What

Vibe step 1 from docs/VIBE-PROJECTS-DESIGN.md. Until now an AI reply overwrote the editor and the saved copy, with no way back (Monaco's setValue clears undo, /api/vibe/save is INSERT OR REPLACE on one column).

• A project is a folder ~/codec-workspace/vibe/<id>/ with a hidden .vibe/ (settings, checkpoint history, stored file versions). No git needed.
• Every AI change is applied as files behind a checkpoint taken before and after. Undo AI change, a Versions drawer (coloured diff, Restore) and Revert to before this on each AI message. Restore and undo write a new checkpoint; nothing is rewritten or deleted.
• A reply with several labelled code blocks fills one editor tab per file while it streams; Stop puts every file back as it was. The preview inlines local css and js.
• Old single-file sessions open as before; the first message sent from one creates a project seeded with what the editor shows. Deleting a project moves its folder to ~/.codec/trash/vibe/.
• VIBE_PROJECTS_ENABLED=false makes the routes answer 404 and the page falls back to single-file Vibe.

Safety

Path rules in safe_rel (no .., absolute, .vibe, .git, links, secret-looking names; 1 MB, 200 files, 50 per reply); one writer (_write_bytes_locked); a damaged history cannot write outside the project. Audit events carry ids and counts only. Page code puts every name and label on the page with textContent.

Checked

• 46 engine/API tests, 28 helper tests, 10 page tests; four deliberate breakages (no link guard, restore keeps new files, undo ignores restores, no checkpoint before an AI change) are each caught.
• 1,074 tests across every file that reads a changed page, route or asset pass; ruff check . clean; skill manifest current.
• Browser, fake AI stream, scratch folders: two-file reply, single reply, Undo, Stop mid-stream, Versions diff + Restore, old session, missing folder, phone width. One real bug found there and fixed.
• Not done: the live dashboard has to restart for the new routes; until then the page falls back to single-file Vibe.

Rollback

VIBE_PROJECTS_ENABLED=false, or revert this PR. The project_id column on vibe_sessions is harmless if left.

Step 2 (three panes, hideable code, live preview) follows in its own PR.

🤖 Generated with Claude Code