[refactor] Sync diagnosis-detection narrowing to sister skills idd-all/idd-list/idd-update (verify follow-up from #53)

[kiki830621]

Problem

From verification of #53 (PR #58):
「Sister substring scans 仍存在 — idd-all/SKILL.md:441,524 (Python substring), idd-list/SKILL.md:115, idd-update/SKILL.md:120 用 ## Diagnosis 做 phase 推斷,同樣 false-positive 風險」
— Source: team:regression + codex

#53 narrow fix 只動 idd-all-chain/SKILL.md。Sister skill 仍有同類 false-positive risk:

• plugins/issue-driven-dev/skills/idd-all/SKILL.md:441 — Python substring if "## Diagnosis" in comment_body
• plugins/issue-driven-dev/skills/idd-all/SKILL.md:524 — same pattern
• plugins/issue-driven-dev/skills/idd-list/SKILL.md:115 — 掃 comments 的標題推斷(prose-level,但底層可能 substring)
• plugins/issue-driven-dev/skills/idd-update/SKILL.md:120 — 同 pattern

#53 Implementation Plan 已 explicit 列為 out-of-scope。本 issue 追蹤是否同步 narrow fix。

Type

refactor (sync narrowing across sister skills)

Priority

P3 (none observed in real-world chain runs to date)

Strategy

For each location:

1. idd-all/SKILL.md:441,524: Python substring → equivalent line-start check (regex ^## Diagnosis on per-comment body)
2. idd-list/SKILL.md:115 + idd-update/SKILL.md:120: 釐清是 prose-only heuristic 還是有底層 jq/grep。若有具體 filter,sync narrow

Acceptance

• Inspect each cited line — confirm whether substring or anchored
• Apply same line-anchor fix as fix: idd-all-chain Step 0.4 jq filter use anchored regex (avoid false-positive on quoted text) #53 if substring
• Smoke test: 對每個 sister skill 跑 quoted-comment fixture 確認 no false-positive

Related

• fix: idd-all-chain Step 0.4 jq filter use anchored regex (avoid false-positive on quoted text) #53 (parent — chain-shell narrowing)
• cluster: chain follow-ups (#49 docs cross-link + #53 jq regex anchor) #58 (PR that fixed chain-shell only)

Source: surfaced during /idd-verify --pr 58 (cluster #49 #53), Step 5b triage. Master report: #58 (comment)