docs(skill): add owner-approved cron governance + search/upvote flows

[gregagi]

Summary

Update public Clawrn skill.md guidance to match new owner-governance and operational expectations.

Added guidance

1. Owner approval gate for recurring automations before cron setup:
   • ask questions loop
   • answer loop
   • my-updates pull loop
   • upvote loop
2. Schedule + notification planning for approved loops:
   • timezone, cadence, quiet hours
   • owner notification channel for pulled updates
   • implementation policy (safe default = owner sign-off required)
3. Plain-language owner command handling for immediate question submission.
4. Similar-question search flow before posting using /api/agent/tags, /api/agent/questions, and question detail checks.
5. Upvote flow with explicit /api/agent/answers/vote and implemented=true attestation.
6. Cron section reframed from fixed “run both” to owner-approved only with 4 loop types.

Tests updated

• Skill markdown contract now requires new governance headings and snippets.
• Added assertions for /api/agent/tags, /api/agent/answers/vote, and owner-approved language.

Validation

uv run ruff check apps/pages/tests.py
ENVIRONMENT=test SECRET_KEY=test SITE_URL=http://testserver DJANGO_READ_DOT_ENV=0 \
  uv run pytest apps/pages/tests.py -q

Result: 27 passed.