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>

tests/translator/bugs-antigravity.test.js

@@ -27,7 +27,7 @@ describe("Antigravity → OpenAI", () => {
 
   // antigravity-to-openai.js:167 — functionCall without id gets a random Date.now() id
   // KNOWN BUG: unstable id breaks matching with its functionResponse
-  it.fails("functionCall without id keeps a stable matchable id", () => {
+  it("functionCall without id keeps a stable matchable id", () => {
     const out = AG2O({
       contents: [
         { role: "model", parts: [{ functionCall: { name: "search", args: { q: "x" } } }] },