fix: harden relay profile configuration updates

[superman2003]

Summary

• make model catalog, config.toml, and auth.json updates share one locked transactional write path with rollback
• reject malformed relay profiles and invalid or overflowing model window values
• keep relay profile UI, persisted settings, and live Codex files consistent on save and delete failures
• fix stale per-model catalogs, suffix updates, unmanaged context preservation, and custom catalog cleanup
• recognize the official ChatGPT Desktop package in the Windows watcher
• stabilize model window row keys and add frontend validation

Tests

• cargo fmt --all -- --check
• cargo check -p codex-plus-core
• cargo test -p codex-plus-core --tests --no-fail-fast
• cargo test -p codex-plus-data --no-fail-fast
• node --experimental-strip-types --test src/model-windows.test.ts (11 passed)

Environment notes

• cargo test --workspace reached the Tauri manager but could not compile generate_context because frontend dist is absent; this checkout has no node_modules, so vite and tsc were not installed locally
• codex-plus-launcher compiled, but Windows refused to execute its requireAdministrator test binary without elevation (os error 740)