This refactoring introduces CLI argument overrides for sandbox and approval policy settings in remote mode, allowing users to specify security constraints via `--sandbox` and `--ask-for-approval` flags.
Changes:
- Add `CodexCliOverrides` type and `parseCodexCliOverrides()` utility to parse CLI flags like `--sandbox`, `-s`, `--ask-for-approval`, `-a`, along with convenience flags (`--full-auto`, `--dangerously-bypass-approvals-and-sandbox`)
- Extract complex start config building logic into `buildCodexStartConfig()` function with proper approval policy and sandbox resolution based on permission mode
- Thread `codexCliOverrides` through the session/loop/launcher chain and apply overrides only when permission mode is 'default'
- Update `codexRemoteLauncher` to use the new config builder and display appropriate warnings based on whether overrides are present
- Add comprehensive tests for both parsing and config building functions
