Allow opt-in outbound networking for Docker computers

[kevinaimonster]

What changed

Docker computers always used --network none, so terminal commands could not download dependencies or call HTTP APIs. Add COMPUTER_NETWORK=bridge as an explicit opt-in while keeping none as the default. Creation and attachment checks enforce the configured network; extra or mismatched networks are rejected. Existing nonroot, filesystem, capability, resource, ownership and unpublished-port checks remain in place.

Expose the selected mode in agent instructions/tool descriptions and keep the terminal UI from suggesting a Desktop tab for network-enabled Docker computers. Include CA certificates in the computer image so Python and git can verify HTTPS. Document configuration, the retained-volume recreation procedure and bridge destination scope.

Verification

• pnpm lint: passed (one existing Biome schema-version informational message).
• pnpm typecheck, worker typecheck and pnpm build:server: passed.
• pnpm test: 486 passed, 0 failed.
• Real Docker smoke test against the rebuilt image: passed, including default network denial, populated CA store, command receipts, PDF transfer, persistence and interruption.
• Live bridge-mode checks through ComputerService: Python verified HTTPS to example.com and PyPI returned 200; Node fetch returned 200. A real DeepSeek tool loop fetched example.com and reported its actual title.
• Local demo migration preserved all 17 existing workspace file hashes and all 7 existing conversations. Its 17 chat/transport/HTTP regression checks passed.

Integration limits

Changing the network mode requires stopping and recreating the computer container while retaining its workspace volume; API and task workers must use the same setting. Bridge mode permits destinations reachable through Docker, including private networks, and does not enforce the browser worker's destination policy or reviewed-write gateway. No ports are published.

The terminal change is text-only; browser visual verification was unavailable because local browser automation is blocked by administrator policy. No screenshot is provided. E2B desktop cloud runtime was not exercised for this change.