Phase 3: coaching preferences + weekly check-in engine

Add coaching preferences (auto-derived from the profile, user-overridable) and
a periodic check-in engine that quotes the person's own words and asks whether
their direction still feels valid — mirror, not compass.

- Preferences are deterministic: a documented triad mapping (gut → direct/
  higher-friction, heart → warm/drift-sensitive, head → reflective/question-led)
  produces defaults for the six fields (coaching_frequency, coaching_style,
  misalignment_threshold, friction_tolerance, prefer_questions_over_directives,
  time_of_day_preference). PUT overrides; regenerate re-derives.
- CheckinCoach (app/services/coaching.py): Anthropic-backed; writes a check-in
  that quotes the person's goals back and asks if the direction still holds.
- Endpoints (app/routers/coaching.py): GET/PUT/regenerate preferences;
  GET/POST checkins; respond (records still_valid); admin POST /run is the
  weekly batch (due = cadence elapsed + locked profile), intended for a cron.
- Models + migration 005: coaching_preferences (per user) and coaching_checkin.
- Frontend: coaching.html (preferences form + check-in feed); linked from
  profile.html.

Tests: 68 passing (added deterministic-preference unit tests and coaching
endpoint/batch tests; run in-container). README updated for Phase 3.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tests/test_static_discovery.py

@@ -48,6 +48,20 @@ def test_profile_page_links_to_reflection():
     assert "/static/reflect.html" in html
 
 
+def test_coaching_page_uses_coaching_endpoints():
+    """Phase 3 coaching page drives preferences + check-ins via authedFetch."""
+    html = Path("app/static/coaching.html").read_text(encoding="utf-8")
+    assert "/discovery/coaching/preferences" in html
+    assert "/discovery/coaching/checkins" in html
+    assert "authedFetch" in html
+    assert "user_id" not in html
+
+
+def test_profile_page_links_to_coaching():
+    html = Path("app/static/profile.html").read_text(encoding="utf-8")
+    assert "/static/coaching.html" in html
+
+
 def test_auth_helper_sends_credentials_and_refreshes():
     js = Path("app/static/auth.js").read_text(encoding="utf-8")