[#966] Reseed worktree CLAUDE.md alongside AGENTS.md

[realproject7]

Closes #966

Summary

Auto-reseed (server/routes.js _performReseedWrites) refreshed a project's worktree AGENTS.md on every template upgrade but never CLAUDE.md, so after a template update the two instruction files drifted (AGENTS.md = new, CLAUDE.md = old). This adds a CLAUDE.md refresh to the same per-target loop, merged through the existing reseedAgentsMd helper (fresh template wins per-H2, operator-added H2 sections preserved).

Core design constraint — never clobber a project's OWN hand-authored CLAUDE.md. Setup only wrote the template CLAUDE.md when a worktree had none, so a worktree's CLAUDE.md may be entirely project-authored. A new pure predicate _isSeededClaudeMd() refreshes a worktree CLAUDE.md only when it carries the QuadWork template's signature H2 set (## Multi-Agent System + ## GitHub Workflow + ## Communication Rules) — three distinctive headings stable across template versions that a project's own dev rules won't have. Anything else (foreign, empty, or missing) is left byte-identical and recorded in skipped.

Return shape unchanged: CLAUDE.md outcomes join the existing {reseeded, skipped, preserved} arrays/map (<agent>/CLAUDE.md keys). Both the manual reseed endpoint and the version-upgrade auto-reseed run through _performReseedWrites, so both now keep CLAUDE.md in sync.

EPIC Alignment

EPIC #967 — folded / isolated (per the batch brief). No sibling contracts to reconcile; this ticket stands alone. The change is confined to the reseed write path and does not alter EPIC-tracked surfaces.

Self-Verification

Adversarial diff re-read — the only production change is the CLAUDE.md block inside _performReseedWrites plus a pure predicate + its export. AGENTS.md handling above it is untouched.

Kill-list / safety invariants:

• Do NOT change AGENTS.md reseed behavior — AGENTS.md write path is byte-for-byte unchanged; existing reseedAgentsMd / token-preservation / auto-reseed tests pass.
• Never overwrite a non-QuadWork CLAUDE.md — _isSeededClaudeMd fail-closed: empty/null/foreign → false → skipped, verified byte-identical in test.
• No CLAUDE.md handled without error — missing file → skipped (<agent>/CLAUDE.md (none)), no file created.
• Consumers unaffected — preserved is echoed as-is in the JSON response and the auto-reseed log only reads reseeded.length / skipped.length; the frontend (ControlBar.tsx) reads only reseeded.length. Mixed preserved key format is display-only.

Build + test evidence:

• npm test → 62 passed, 0 failed, 2 skipped (pre-existing Jest-style skips).
• New server/routes.reseedClaudeMd.test.js: predicate unit cases + endpoint E2E (seeded refreshed & operator H2 preserved; foreign left byte-identical & skipped; missing handled without error; AGENTS.md still refreshed).
• node server/pack-smoke.test.js → PASS.
• node -e "require('./server/routes.js')" → loads OK.

Acceptance criteria (1:1):

• Reads templates/CLAUDE.md, substitutes {{project_name}}, merges via reseedAgentsMd ✅
• Seeded CLAUDE.md refreshed + operator H2 preserved ✅ (test)
• Foreign CLAUDE.md left byte-identical / skipped ✅ (test)
• No CLAUDE.md handled without error ✅ (test)
• Reports refreshed/skipped in {reseeded, skipped, preserved} ✅

Deviations

• Signature-detection over provenance-marker (both offered in the ticket). The signature approach recognizes CLAUDE.md files seeded by older templates — which is exactly the existing-upgraded-user population auto-reseed serves. A provenance marker would only match files seeded after it shipped, stranding every already-installed worktree; it would also require editing the setup seed paths (expanding scope and AGENTS-adjacent surface). No setup-path changes were needed.
• The preserved-notes trailer emitted by the reused reseedAgentsMd reads <!-- Operator notes preserved from prior AGENTS.md (#845) --> even inside a merged CLAUDE.md. Cosmetic; left as-is because the ticket directs reuse of the same helper unchanged.

[project7-interns]

Verdict: APPROVE

Epic Alignment: PASS

#966 requires CLAUDE.md reseed through existing per-H2 merge semantics while preserving AGENTS.md behavior and never overwriting foreign CLAUDE.md; PR #993 implements that in server/routes.js:4390 with coverage in server/routes.reseedClaudeMd.test.js:137.

Checked (evidence)

• Structural gate: gh pr view 993 --json body → filled ## EPIC Alignment and ## Self-Verification; non-UI PR.
• Issue/epic context: gh issue view 966 + gh api repos/realproject7/quadwork/issues/967 → standalone folded ticket under #967; reseed contract is reuse reseedAgentsMd, preserve operator H2s, do not change AGENTS.md behavior.
• Diff scope: gh api repos/realproject7/quadwork/pulls/993/files → exactly server/routes.js (+58) and server/routes.reseedClaudeMd.test.js (+181).
• Acceptance: seeded CLAUDE.md gate at server/routes.js:4160; reseed/skip/report path at server/routes.js:4395; endpoint tests cover seeded refresh, foreign byte-identical skip, missing skip, and AGENTS.md still refreshed at server/routes.reseedClaudeMd.test.js:157.
• Riskiest part of this diff: the provenance heuristic could clobber foreign files if too broad; it requires all three stable template H2s and fails closed for empty/missing/foreign cases, with endpoint regression coverage.
• Kill-list: scanned all items — clean.
• CI: gh pr checks 993 → test pass 48s.

Findings

• None.

Decision

Approving at 24160df828049189221b95bce8537434fc84227d; the implementation matches #966's safety constraints and keeps the change local to the reseed path plus focused tests.

[realproject7]

@re2 APPROVE at 24160df828049189221b95bce8537434fc84227d

Scope is exactly the two files claimed: server/routes.js (new predicate + CLAUDE.md block in the reseed loop + test export) and the new server/routes.reseedClaudeMd.test.js. AGENTS.md reseed behavior is unchanged — the CLAUDE.md handling is appended after the existing AGENTS.md write and touches none of it.

Checked (evidence)

• Core no-clobber constraint holds. _isSeededClaudeMd (server/routes.js:4165) requires ALL of SEEDED_CLAUDE_SIGNATURE = Multi-Agent System + GitHub Workflow + Communication Rules. templates/CLAUDE.md carries all three (## Multi-Agent System, ## GitHub Workflow, ## Communication Rules), so a freshly-rendered template is recognized; this repo's own hand-authored CLAUDE.md (H2s: What is QuadWork, Tech Stack, Design Tokens, … — none match) and the test's FOREIGN_CLAUDE are not. Empty/null/read-fail → false (fail-closed).
• Security invariant: the only write to CLAUDE.md (server/routes.js, fs.writeFileSync(claudeMd, mergedClaude.content)) sits inside the _isSeededClaudeMd(claudeExisting) truthy branch. Missing → skipped "(none)", foreign → skipped "(not QuadWork-seeded)", no template → skipped "(no template)". No unguarded path can overwrite a non-QuadWork CLAUDE.md.
• Merge semantics correct. Reuses reseedAgentsMd (fresh template wins per-H2, non-fresh existing H2s preserved under trailer). {{project_name}} substituted with dirName before merge; refreshed CLAUDE.md reported in reseeded, preserved H2s under preserved["<agent>/CLAUDE.md"].
• Parser only matches H2. _splitAgentsMdSections regex ^##\s+(.+?)\s*$ won't capture ###; heading comparison is case-insensitive + whitespace-normalized in both predicate and merger — consistent.
• Tests, independently run at 24160df (fresh worktree, node server/routes.reseedClaudeMd.test.js): all assertions passed. Full reseed suite green: autoReseed, reseedAgentsMd, reseedTokenPreservation, resolveReseedTargets, reseedClaudeMd all PASS. CI gh pr checks 993 → test pass 48s. state OPEN, mergeable MERGEABLE, head unmoved.

Non-blocking nit (no change required): the preserved-notes trailer text is shared with AGENTS.md, so an operator H2 preserved inside a refreshed CLAUDE.md is labeled <!-- Operator notes preserved from prior AGENTS.md (#845) -->. Cosmetic only; behavior is correct.

Standing no-merge rule — operator merges.