chore(search): PR #165 회차 1 리뷰 반영

- HOTFIXES test 카운트 표기 정정: `9 신규 / 갱신 unit test` 의 산수
  ambiguity → `9 unit test (8 갱신 + 1 신규) + 2 신규 통합 test = 11
  total` 로 명시.
- SKILL.md (Claude Code integration) 의 search 절에 column scoping +
  heading_path raw-mode escape hatch 안내 한 bullet 추가. 회차 1
  의 follow-up suggestion 반영 — heading 검색 의도 agent 가 새
  escape hatch `'heading_path : <token>'` 를 발견 가능.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

integrations/claude-code/kebab/SKILL.md

@@ -61,6 +61,7 @@ Input:
 - When `truncated: true`, the budget loop modified the page (snippet shortening or k reduction). `next_cursor` is **independent** — non-null whenever more hits may be reachable. Caller may widen `max_tokens` (re-issue same query for fuller snippets / more hits per page) or follow `next_cursor` (advance through more hits) or both. Mismatched cursor (corpus_revision changed) returns `error.v1.code = stale_cursor` — re-issue the search to obtain a fresh one.
 - **`trace: true` (p9-fb-37)** — debug aid. Response carries an extra `trace` block: `lexical[]` + `vector[]` (pre-fusion candidates), `rrf_inputs[]` (RRF union before final cut), and `timing` (`lexical_ms`, `vector_ms`, `fusion_ms`, `total_ms`). Trace bypasses the search cache (always cold). Use sparingly — it bloats the wire response and is for diagnosing "why did this hit / not hit", not normal retrieval.
 - **`hint` (v0.17.0)** — optional advisory string on `search_response.v1`. Present only when the result is empty AND the trimmed query is shorter than the FTS5 trigram tokenizer's 3-char minimum. Surface it to the user instead of retrying the same short query. Korean lexical search benefits most from ≥3-char keywords (`충돌` zero-hit, `충돌은` substring-hit). Raw FTS5 mode (`'...'`) opts out — the user opted into FTS5 syntax. Vector / hybrid modes carry the field too but it's rarely triggered (semantic embeddings handle short queries).
+- **Column scoping (post-v0.17.1 dogfood)** — default lexical / hybrid matching is scoped to the `text` column only. The `heading_path` column is indexed (path segments like `app`, `src` plus JSON punctuation are 3-gram'd) but excluded from the default MATCH — past JSON noise produced false positives where a query coincidentally shared a 3-gram with a file's heading path. To deliberately search heading paths, escape into raw FTS5 mode with an explicit column filter: `'heading_path : <token>'` (e.g. `kebab search "'heading_path : agent'"`). Same applies to MCP `search` — quote the inner expression. Raw mode bypasses both column scoping and the 3-char `hint` short-circuit.
 
 ### `mcp__kebab__bulk_search`