fix: CLAUDE.md missing worktree/branch cleanup rules after PR #2478 merge

[mrveiss]

Problem

Session on 2026-03-26 added three CLAUDE.md changes for worktree/branch hygiene:

1. Issue completion checklist steps 7-8 (remove worktree, delete branch)
2. New "Worktree & Branch Cleanup (MANDATORY)" section under Branch Strategy with bulk cleanup commands
3. End-of-session ritual step 2 (clean up worktrees & branches for closed issues)

PR #2478 (issue #2467) was merged concurrently, overwriting all three additions. Only the cleanup-worktrees.sh reference on line 416 survived.

Impact

Without these rules in CLAUDE.md, agents will continue leaving stale worktrees and branches after issue closure — the same problem that caused 130+ stale branches to accumulate.

Fix

Re-add the three CLAUDE.md sections. The exact content is documented in this session's conversation. Key additions:

• Steps 7-8 in "Issue is complete ONLY when" checklist
• "Worktree & Branch Cleanup" section with single-issue and bulk cleanup commands
• End-of-session ritual step 2

Discovered During

Worktree/branch cleanup session on 2026-03-26 (151 → 4 branches).

[mrveiss]

Fixed in commit ef67737. Re-added all three CLAUDE.md sections: completion checklist steps 7-8, Worktree & Branch Cleanup section, and end-of-session ritual step 2.