## Description
Implements selective MITM (Man-in-the-Middle) in `aibridgeproxyd` so
that only requests to allowlisted domains are intercepted and decrypted.
Requests to all other domains are tunneled directly without decryption.
## Changes
* New config option: `CODER_AIBRIDGE_PROXY_DOMAIN_ALLOWLIST` (default:
`api.anthropic.com`,`api.openai.com`)
* Selective MITM: Uses `goproxy.ReqHostIs()` to only intercept `CONNECT`
requests to allowlisted hosts
* Certificate caching: Now only generates/caches certificates for
allowlisted domains
* Validation: Startup fails if domain allowlist is empty or contains
invalid entries
Closes: https://github.com/coder/internal/issues/1182
Susana Ferreira
74b6d12a8a