phase: 118_summary_seed_context

**Phase 118 final verification pass — complete.** All criteria verified; 4 pre-existing defects found and fixed.

- **Verified:** summary-seed wiring (`select_suggested` top-5 no-floor → summary blocks, no full text in HIGH prompt), all-doc markdown summaries + NULL backfill (`summary_backfilled`, no `sources_meta` bump), `read` adds full text with `read_docs`-only dedupe, `done.sources` = suggested+read / durable record = suggested+related+read + `suggested=N` log line (seen live in E2E), byte-locked PERSONA/LOW/TOOLS_SECTION, battery gate PASS recorded in `TOOL_CALLING_TESTING.md` §10 (turbo 2026-09-16: 1/2/4 GREEN, cond-3 reported 9/10 per A7, contract 21/21, caps 0).
- **Defects fixed (all pre-existing, none phase-118):** ① `ChatMessage` schema missing the phase-113 `related` key → `extra="forbid"` 422'd every done-time auto-save of grounded turns with a related tier, leaving `message_count=1` (root cause of `test_share_chat` 3F; browser-level instrumentation proved the PUT 422) — added the field + unit/integration pins; ② `test_theme_semantic_completion` pins stale vs phase-117 debox (border/chip removed) — re-targeted to assert border/chip *absence*; ③ `test_header_consistency` `<26`px pin red on 26.125px native date-input line — bound relaxed to `<34` (wrap-detection intent kept); ④ `test_navbar_refresh` bor.chat.v1 key set updated for `related`.
- **Test/lint/coverage:** `uv run pytest --cov=app --cov-report=term-missing` → **2506 passed, app/ 99%** (>90%); `uv run ruff check . && uv run pyright` → clean, 0 errors.
- **E2E:** new story suite in isolation → **2 passed**; full 103-suite matrix sweep (each isolated) → **all 103 green** after the fixes; `test_share_chat` 4 passed, `test_theme_semantic_completion` 8 passed, `test_header_consistency` 3 passed, `test_navbar_refresh` 7 passed.
- **Deviations:** none from LOCKED decisions. Note: orphaned diagnostic uvicorn processes briefly made E2E sessions exercise stale code — killed and re-verified; a sweep-regenerated tracked screenshot was restored. No commits made (harness commits).
- **Completion criteria:** all 7 ✅ (commit/phase-move is the harness's step).
- **Next pending phase:** none — `todo/` holds only this phase's overview pending the harness move.

.env.example

@@ -38,6 +38,8 @@ BOR_RELEVANCE_THRESHOLD=0.62      # answer when best cosine >= this OR an FTS hi
 # BOR_LEXICAL_SUPPORT_FLOOR=0.35  # cosine floor for FTS hits to flip HIGH (A8 revised 2026-09-14); 0 <= floor <= relevance_threshold
 # BOR_SOURCE_USEFULNESS_FLOOR=0.35 # cosine bar for a citation slot (phase 113): a doc earns done.sources only when its best-chunk cosine clears it; 0 <= floor <= relevance_threshold; 0 = no bar
 # BOR_RELATED_MAX_DOCS=2            # cap on the related-doc tier in the done frame (phase 113: the UI's de-emphasized "nearby docs" row, never a citation chip); 0 = no related docs
+# BOR_SUGGESTED_DOCS=5              # cap on the "start here" suggestion tier (phase 118): top-N doc summaries seeded into the grounded prompt; NO cosine floor (opt-in starting points, not citations); >= 1
+# BOR_SUGGESTION_PREVIEW_CHARS=400  # NULL-summary fallback preview in a suggestion block (phase 118): first N content chars + the truncation marker; > 0
 BOR_MAX_OUTPUT_TOKENS=32768       # max answer length in tokens (answers must not be cut off)
 BOR_STEERING_MAX_CHARS=8000       # char budget for the <tuning> (steering notes) prompt section
 BOR_SUMMARY_MAX_CHARS=12000       # cap on document content sent to the lite summary model (phase 30)