feat(nightshift): add automated codebase maintenance system

[Loa212]

Summary

Adds Nightshift — an automated codebase maintenance system that runs configurable checks in the background using real Claude CLI sessions.

What's included

Rust backend (src-tauri/src/nightshift/)

• Engine with sequential check execution per project, concurrent across projects
• 10 built-in checks: lint-fix, dead-code removal, doc-drift, security audit, test gaps, dependency audit, type safety, error handling, performance review, config hygiene
• Per-project configuration: enable/disable checks, schedule time (HH:MM cron), post-action (nothing / commit / commit & PR), model/provider/backend overrides, per-check custom prompts and cooldown overrides
• Atomic JSON storage with lock protection, max 50 runs per project, per-check cooldown tracking
• RUNNING_PROJECTS guard prevents concurrent runs on the same project

Frontend (src/)

• NightshiftPane in Project Settings with experimental banner, enable toggle, "Run Now" button, per-check config
• NightshiftRunsModal with run history and collapsible check results
• useNightshiftEvents hook: listens for nightshift:execute-check, sends messages to CLI sessions, reports completion back to engine
• Zustand store + TanStack Query service layer

Integration points

• Nightshift worktrees are created programmatically using save_empty_index() and worktrees:changed event from PR test(chat): add test for WorktreeIndex::new_empty() #120
• Session metadata tracks source, nightshift_check_id, nightshift_run_id
• Respects custom worktree directory from PR feat(projects): add per-project worktree location configuration #117

(NICE-TO-HAVE) Token usage / cost tracking

Token usage tracking and budget limits are not yet implemented. Citing the inspiration (see below):

Budget-aware: Uses remaining daily allotment, never exceeds configurable max (default 75%)

Inspiration

Inspired by marcus/nightshift

[andrasbacsai]

Oh wow, nightshift sounds pretty good! Thanks I will take a look at it!

[Loa212]

@andrasbacsai sorry I have to make some changes. I will tag you later once I feel it is ready for review again. Thanks !

[Loa212]

@andrasbacsai tested this with both Claude and Codex. It's marked as experimental, living in each project's settings under a "Nightshift" tab. You can hit Run Now to try it out immediately.

Built-in checks (8 enabled by default, 2 opt-in):

• Lint Fix — auto-fix linting and code style violations (24h cooldown)
• Dead Code Removal — find and remove unused imports, functions, variables (72h)
• Documentation Drift — fix stale/missing/inaccurate docs and comments (48h)
• Security Audit — OWASP top 10, hardcoded secrets, injection vulnerabilities (7d)
• Test Coverage Gaps — write tests for untested code paths and edge cases (72h)
• Dependency Audit — update outdated/deprecated/vulnerable dependencies (7d)
• Type Safety — replace any types, add missing annotations (48h)
• Error Handling — fix empty catches, swallowed errors, poor messages (48h)
• Performance Review — N+1 queries, memory leaks, unnecessary re-renders (7d, opt-in)
• Config Hygiene — clean up unused config keys, env gaps (7d, opt-in)

-> Each check has its own cooldown, can be individually enabled/disabled, and you can override the prompt per-check.

-> You can set a schedule time for automatic overnight runs, and choose what happens after: leave changes staged, commit, or commit & open a PR.

Since Codex now has usage tracking we could hook this up to show nightshift costs, or we can wait for stable Claude usage support. Let me know what you'd prefer.

Overall let me know what you think. I believe this can be a nice addition but you decide :)

If you want it shaped differently I'm open to suggestions.