Implementation Notes: Issue 58 Windows Scaffold Setup Mirrors

Validation Evidence

• RED: bun run --cwd apps/cli test src/data/scripts/sync-subagents.test.ts in /tmp/harness-issue58-red.f6j6jd after applying only the new tests to HEAD failed on Claude settings preservation and EPERM mirror fallback.
• GREEN: bun run --cwd apps/cli test src/data/scripts/sync-subagents.test.ts.
• GREEN: bun run --cwd apps/cli test src/data/scripts/sync-subagents.test.ts src/scaffold/run.test.ts src/update/run.test.ts.
• GREEN: bun run --cwd apps/cli check-types.
• GREEN: bun run --cwd apps/cli check.
• GREEN: git diff --check.

Implementation Notes

• sync-subagents.mjs now merges generated Claude hook entries into existing .claude/settings.json, preserving unrelated fields, user hook entries, and permissions allow-lists.
• Managed prompt, hook, and skill mirrors now try Windows directory junctions for directory targets and copy files or directories when symlink creation fails with EPERM.
• CLI scaffold docs record the Windows fallback and Claude settings merge contract.

Manual Review Checklist

• Windows mirror fallback preserves setup completion when symlink creation is blocked.
• Claude settings merge preserves existing non-hook settings and permissions.
• Generated prompt output remains repo-specific.
• Docs mention the Windows fallback and Claude merge contract.