Control: multi-end branch/worktree discipline

[Osbornx21]

Branch strategy for multi-end Codex work:

• main is public shared baseline at 4fa66c8.
• Use codex/-YYYYMMDD branches for feature slices.
• Do not push secrets, dist packages, provider outputs, raw audio, or hardware local credentials.
• Keep host/mock/candidate evidence separate from physical PRD acceptance.