Omega v0.2.0-rc20

Omega v0.2.0-rc20

• Removes all Omega runtime use of macOS Keychain and stores credentials and identity in private local files.
• Reuses hosted Omega grants across restarts and reports hosted usage limits accurately without futile retries.
• Runs delegated Codex and Claude sessions unattended while keeping every delegation card independently expandable.
• Includes the latest Omega-only executor, sidebar, settings, error presentation, and authentication fixes.

SHA-256: 8f6ee5730e1db16689314047e60baef7278c8ea3c3320b73377ca268c3d3f871