## What changed
Add `create_command_args()` to encode argv, permissions, policy cwd, and optional managed network context through the existing bounded environment transport.
For managed networking, generate a policy that allows IPv4 and IPv6 loopback while denying direct non-loopback egress and general inbound access. Require nonempty, nonzero proxy ports and reject `allow_local_binding=false` at both launcher and policy boundaries because native host-loopback access is bidirectional.
Document the MXC launch contract, platform requirements, and limitations.
## Testing
Add portable tests covering managed network transport and policy translation, plus rejection of missing proxy ports, zero ports, and unsupported local-binding restrictions at both boundaries.
GitOrigin-RevId: 8d31b98f94a2ba3769369aa50de8e53dc143bac4
## Why
Sandbox policies can exceed Windows command-line limits. Provide an environment transport for these larger MXC launch requests.
## What changed
- Make `MxcCommand` serializable and add JSON encoding and decoding through `CODEX_MXC_LAUNCH_*` environment variables.
- Split payloads into UTF-8-safe chunks of at most 4,096 bytes, with a 1,000,000-byte payload limit and at most 256 chunks.
- Reject malformed or duplicate transport entries and remove all transport variables during decoding, including on failure. Preserve unrelated environment variables.
## Testing
Add tests for large Unicode and escaped-argument round trips, stale variable removal, malformed transport rejection and cleanup, and oversized payload rejection without modifying the environment.
GitOrigin-RevId: 0e5ae2535ef313985a95eb8a5fd4884974dfb1eb
iceweasel-oai