phase: 103_suggestions_session_openers

Phase 103 final verification pass — all green.

**Verified (all 3 tasks already in `complete/`; no code changes needed):**
- `opening_questions` in `app/api/suggestions.py` — forward walk, one opener per chat (first non-blank user msg, A3), reads raw `messages` not `title` (A4), phase-80 order/dedup/cap/seed contracts; `last_questions` name gone from `app/`+`tests/`
- Docs updated: `app/config.py` seed docstring, `.env.example` `BOR_SUGGESTIONS`, `README.md` — "session openers" wording
- Diff scope correct: only the 6 expected files + phase-file moves; `app/rag/suggestions.py` and `frontend/` untouched

**Test / lint / coverage results:**
- `uv run pytest tests/integration/test_suggestions_api.py -v` → 12 passed
- `uv run pytest tests/e2e/test_suggestion_chips.py -v --no-cov` → 8 passed in isolation (opener-only core pin included)
- `test_responsive_polish.py` → 7 passed; `test_chat_persistence.py` → 4 passed (both isolated, no edits)
- `uv run pytest --cov=app --cov-report=term-missing` → 2086 passed, TOTAL 99% (>90%); `app/api/suggestions.py` 100%
- `uv run ruff check .` → clean; `uv run pyright` → 0 errors, 0 warnings

**Completion criteria:** all 7 ✅ (follow-ups-never-surface pin; cap-across-chats pin; seed/dedup/case/partial/A3/401 pins; E2E suites isolated; deflection chips unchanged; full suite + lint; commit + dir move left to harness per executor rules).

**Deviations:** none — no defects found; nothing changed in this pass.
**Next pending phase:** `98_sync_summary_visibility` (numeric order in `todo/`).

.env.example

@@ -60,7 +60,7 @@ BOR_RRF_K=60                      # Reciprocal Rank Fusion damping constant
 # insensitive, no partial names — phase 102). A blank list or a
 # malformed token (e.g. md,sh!) fails startup loudly, naming the value.
 BOR_IMPORT_EXTENSIONS=md,markdown,txt,yaml,yml,json,py,container,network,volume,image,pod,kube,swap,os,endpoint,j2
-# BOR_SUGGESTIONS=["How is my Kubernetes cluster set up?"]   # JSON seed chips — shown only before any question has been saved (phase 80)
+# BOR_SUGGESTIONS=["How is my Kubernetes cluster set up?"]   # JSON seed chips — shown only before any question has been saved (phase 80); after that the chips are the 3 newest chats' opening questions (phase 103)
 
 # --- Import sources (git; phase 28, admin-managed since phase 35) ---
 # Comma-separated git repo URLs; import_docs clones each (first run) or