## Why
Destination restrictions and policy revocation must remain effective during redirects, response body reads, and established WebSocket traffic. Policy denials must also survive error handling so callers do not retry them or report a revoked operation as successful.
## What changed
- Route managed HTTP clients through a shared `RequestBuilder` and policy-aware execution, checking each redirect destination before route resolution and retaining a network permit while consuming response bodies.
- Guard WebSocket connection setup, reads, and writes with revocable permits, including independent wakeups for split readers and writers.
- Preserve `TransportError::Policy` through HTTP, SSE, and realtime error handling, and treat policy denials as non-retryable.
- Keep the supplied network policy in plugin startup HTTP requests and propagate response body failures from backend and plugin requests.
## Testing
Add regression coverage for rejection before connecting, revocation during redirect routing and streamed body reads, split WebSocket revocation, realtime writer error propagation, and revoked plugin upload responses.
GitOrigin-RevId: fba36700444c98a8364c09b4dc5452c4d78a90fb
## Why
Local MCP requests can fail when the platform TLS backend cannot negotiate a
protocol version with an HTTPS endpoint.
## What changed
- Retry replayable local MCP requests once with rustls after a recognized TLS
protocol-version negotiation failure. Keep certificate, timeout, and unrelated
connection failures on the existing error path.
- Remember successful fallback per HTTPS origin and outbound route, while keeping
the platform TLS backend as the default for other destinations.
- Share the fallback-enabled client across local MCP resolution, CLI login, and
OAuth discovery while preserving remote environment HTTP clients.
## Testing
Added coverage for platform-specific error detection, request replay, cached
fallback reuse and isolation, non-replayable requests, redirects, and remote MCP
client selection.
GitOrigin-RevId: 39a2d96fdb2ea0e51df14f652ba2a953d24e69a1