PR Hygiene rules

If a PR adds new TODO/FIXME comments, require a tracking ticket. Preferred formats: `TODO(ABC-123): ...` or `FIXME(ABC-123): ...`. If a ticketing MCP is available, suggest (or create) the ticket and link it in the PR. Avoid leaving untracked TODOs in mainline code.

If the change affects users or operators, update end-user docs/runbooks and add a concise changelog entry in the PR description or designated file.