## Why
Application network restrictions need to cover clients created by the TUI and `codex exec` before embedded app-server startup, and remain effective when configuration is rebuilt.
## What changed
- Introduce `EmbeddedNetworkPolicy` to share live policy between caller-owned transports and the embedded app-server.
- Apply loaded requirements before creating telemetry, background HTTP clients, and executor connections. Limit authentication and cloud configuration bootstrap requests to exact endpoints under local policy.
- Preserve the shared policy across TUI session changes, permission-profile rebuilds, and worktree cloud loaders so existing clients observe policy reloads and failures.
- Document application network policy behavior and transport coverage.
## Testing
Add regression coverage for policy activation, reload failure and recovery, retained policy across TUI rebuilds, rejected OAuth and cloud-policy redirects, and workspace network restrictions with `CODEX_API_KEY`. Also cover retaining the caller-selected project during embedded startup.
GitOrigin-RevId: 629009f087b8cb21fc34a1ee7ea6fe95d9e0f2b5
## What changed
- Load `application.network` requirements at startup and explicit config/account reloads, applying local policy before authentication and cloud configuration bootstrap.
- Block traffic when policy loading fails, cancel requests that a new policy no longer permits, and reject configuration loads based on superseded policy snapshots. Local requirements edits take effect on the next explicit reload or restart.
- Bind authenticated clients to the current account and revoke them when account ownership changes. Carry policy enforcement through backend requests, realtime connections, workload identity exchanges, and code-mode gRPC streams while preserving gRPC trailers.
- Treat denied credential refreshes as policy errors without retrying them or invalidating stored credentials.
## Testing
Add regression coverage for startup restrictions, reload ordering, cancellation after restrictive or malformed requirements edits, account revocation, gRPC destination denial, workload identity cancellation, and credential preservation after denied OAuth refresh.
GitOrigin-RevId: 0cb4c720a906397e9df06675f01ecf60d741101f