fix(translator): ESM-safe registry + tool-id pairing + responses max_tokens; add real-creds tests

- translator/index.js: replace require() with static side-effect imports (ESM-safe),
  lazy-init registry maps to survive circular import order
- openai-responses->openai: map max_output_tokens -> max_tokens (avoid leaking field upstream)
- gemini/antigravity -> openai: derive deterministic tool_call id from name so
  functionCall/functionResponse pair correctly (fixes provider tool-pairing 400s)
- add offline unit tests (finish-reason, usage, session-manager, ollama malformed args, const guard)
- add real-creds integration tests (provider-cases + all-formats matrix: 6 inbound formats x 4 scenarios)

Includes co-located provider registry refactor (pricing/capabilities/media providers) and sessionManager updates.

Co-authored-by: Cursor <cursoragent@cursor.com>

open-sse/handlers/chatCore.js

@@ -88,6 +88,9 @@ export async function handleChatCore({ body, modelInfo, credentials, log, onCred
   const clientTool = detectClientTool(clientRawRequest?.headers || {}, body);
   const passthrough = isNativePassthrough(clientTool, provider);
 
+  // Expose raw client headers to translators/executors for session-id resolution
+  if (credentials) credentials.rawHeaders = clientRawRequest?.headers || {};
+
   let translatedBody;
   let toolNameMap;
   if (passthrough) {