feat(cron): add the host OS crontab to the /cron page

[Mktotoy]

Summary

The /cron page only surfaced Claude Code's session-scoped CronCreate jobs. This adds a second, read-only section showing the host machine's real cron daemon, grouped by origin so a user's Claude skill crons stand out from OS noise.

Changes

• New API router routers/system_cron.py → GET /cron/system:
  • reads the user crontab (crontab -l), /etc/crontab, /etc/cron.d/*, and the run-parts periodic dirs; each source fails independently and never blocks the others
  • classifies every entry by origin: claude-skill (with the skill name extracted), claude, system, user — command path wins over source
  • origin detection honours a custom CLAUDE_KARMA_CLAUDE_BASE, with a ~/.claude fallback, and normalises path separators
  • cross-platform: Linux + macOS/BSD; on Windows returns a clean supported: false payload (no cron daemon there) instead of erroring
  • next-run inferred via croniter where the expression is parseable
• New self-fetching component SystemCrontabSection.svelte: collapsible groups per origin, colored badges, sorted by next run, system group collapsed by default, graceful empty / unsupported / error states
• Additive wiring only: one import + one include_router in main.py; one import + one tag in cron/+page.svelte

Component

• API (FastAPI backend)
• Frontend (SvelteKit dashboard)
• Captain Hook (hook models)
• Hook Scripts
• Documentation
• CI / Build

Type

• Feature (new functionality)

Testing

• API tests pass (cd api && pytest tests/test_system_cron.py → 24 passed; full suite green except one pre-existing, unrelated test_background_shells env test that also fails on main)
• Frontend type-checks (npm run check → 0 errors; new files add no warnings)
• Frontend lints clean (npm run lint → 0 errors in new files)
• Captain Hook tests pass — N/A (no hook-model changes)
• Manually tested (endpoint returns parsed crontab; /cron renders HTTP 200)

Screenshots

Omitted — developed in a headless CLI environment. Happy to attach a screenshot of the grouped section on request.

Related Issues

None.

[JayantDevkar]

Approved ✅

Verified end-to-end on macOS — worktree off this branch, FastAPI on :8000 + SvelteKit on :5173, driven via Playwright. Works as described.

Backend (GET /cron/system)

• Empty / supported:true payload on a host with no crontab; correct cross-platform shape.
• With a representative crontab: correct origin classification (claude-skill / claude / user), skill-name extraction, PATH= env line filtered, by_origin / by_source aggregation.
• Description enrichment: inline comment wins over SKILL.md; SKILL.md fallback is first-sentence-truncated.
• schedule_human + croniter timeline correct across */30, 0 */2, 0 3, 30 9, @daily, * * * * *, 5 4 * * 0; @reboot → "at boot" with next_run: null (graceful).
• Probes: POST → 405, bad include_periodic → 422, endpoint present in OpenAPI.
• Tests: pytest tests/test_system_cron.py → 39 passed (no CI ran on this fork PR, so I ran it locally).

Frontend (/cron)

• Source toggle with ?source=system URL persistence; stat strip reacts to the toggle; origin filter chips (only existing origins shown); expandable per-entry fire-timeline (past / now / upcoming).
• Self-fetch GET /cron/system → 200, 0 console errors; renders cleanly in dark mode (design tokens). Original Claude-crons view ({:else} branch) untouched.

One non-blocking nit: next_run is a fetch-time snapshot, so a fast job's relative label drifts stale (an every-minute job went "now" → "2m ago" without a reload). The Reload button covers it; a periodic re-fetch / client recompute would make it self-correcting. Fine to land as-is.

Clean, strictly-additive change. 👍

[JayantDevkar]

Re-approving — my prior approval was dismissed by the new push. The only change since is afc35a46 (fix(tests): move system_cron test into tests/api so it runs with fastapi): a pure rename of the test file + a one-line sys.path depth fix, no source/frontend changes. Full CI matrix is green on this head. Verification from my earlier review still stands.