[codex] add scheduling dashboard and auth recovery

[steven-haddix]

Summary

• add a dedicated usage view and scheduling view with dispatch configuration UI
• add backend dispatch coordination and shared scheduling/usage state plumbing
• harden Claude auth recovery by reloading rotated credentials and clearing stale cached auth after refresh failures

Why

• the app now supports scheduling saved Claude and Codex commands around reset windows
• the auth fix addresses a restart-only recovery path where stale in-memory Claude credentials could keep failing until the app was reopened

Impact

• users can manage dispatch jobs from the app UI
• usage polling recovers more gracefully when Claude credentials rotate outside the app

Validation

• cargo test --manifest-path src-tauri/Cargo.toml
• bun run test