Codex issue coordinator

Use one Codex thread to coordinate a GitHub issue batch. Give each active issue its own worker thread, worktree, branch, and pull request. Workers hold implementation context. GitHub holds dependency state.

Explicitly naming /codex-issue-coordinator, or explicitly telling the coordinator that agents may merge, authorizes in-scope workers to merge their own pull requests after every merge gate below passes. An implicit skill match does not grant merge authority: run in no-merge mode unless the user's words grant it. Neither mode authorizes deployment, release publication, destructive operations, branch-protection bypasses, or changes outside the supplied batch.

Preconditions