feat: release pexo-agent 0.3.12

[Naniko0213]

Summary

• add explicit credit confirmation handling and machine-readable credit failure routing
• harden local API-key configuration parsing and permissions
• fix final-video delivery routing and preserve attachment events
• align the official ClawHub target with pexo-video-agent and fail publishing errors visibly
• add Codex UI metadata and remove stale legacy ClawHub metadata

Verification

• strict Agent Skill validation passed
• all shell scripts pass bash -n and --help checks
• config precedence and command-injection regression checks passed
• production API diagnostics and read-only project polling passed
• production URL checks passed
• no secrets, test endpoints, or legacy ClawHub identities found in the package

Release

After merge, publish this package to pexo/pexo-video-agent as 0.3.12.