- Preserve API key entries with empty `api_key` when `base_url` is configured, and extend config dedupe/ID logic to include base URL, proxy, prefix, and headers so identities are stable.
- Update config/auth handling so `auth_kind=apikey` is treated as config API-key auth even without an `api_key` field, enabling base_url-only credential records.
- Ensure Gemini/Codex/XAI request path clears `Authorization`/provider auth headers when token is empty to avoid leaking unrelated auth state.
- Propagate request headers into custom-header resolution for OpenAI/Gemini/XAI/Codex execution and websocket flows.
- Resolve auth `header:` values like `$ABC` from incoming request headers at request time and omit headers when no value is available.
- Add documentation for the dynamic custom-header behavior in `config.example.yaml`.
Closes: #5053
- Added `is-compat` model metadata plumbing from config through executor and helpers, including hash computation.
- Introduced a compatibility-aware translation path (`TranslateRequestWithAPIKeyModelCompatibility`) and wired it into Claude/Gemini/Codex/Interactions request flows.
- Updated Claude message sanitization/translation behavior to keep empty-thinking compatibility blocks (including signatures) when `is-compat` is enabled, while keeping default behavior unchanged.
- Introduced `disable-codex-cloaking` to allow disabling enforced `User-Agent` and `Originator` headers for Codex requests.
- Updated header application logic to conditionally include `codexUserAgent` and `codexOriginator` based on configuration.
- Enhanced config diff tracking to detect changes in `disable-codex-cloaking`.
- Expanded tests to cover new config behavior and header application scenarios.
- Removed deprecated interceptor and executor-related methods, including `callRequestInterceptor`, `callResponseInterceptor`, and `callStreamChunkInterceptor`.
- Consolidated unused logic and pruned redundant imports to streamline `adapters.go`.
- No functional changes.
