fix: preserve protocol parity across compatibility hops (#259)

* wip: preserve local changes before upstream merge

* Improve proxy routing stability and add stable-first strategy

* Sync explicit-group routing strategy to eligible source routes

* Fix proxy retry and runtime health review issues

* fix: make proxy channel retry attempts configurable

* fix: harden proxy retry recovery and bookkeeping

* fix: address pr 257 review comments

* fix: preserve oe tool_result structure

* fix: preserve protocol parity across compatibility hops

* fix: satisfy server build and typecheck

* fix: preserve codex and mcp fallback semantics

* fix: address ci and review follow-ups

---------

Co-authored-by: bnvnvnv <bnvnvnv@gmail.com>

src/server/proxy-core/providers/codexProviderProfile.ts

@@ -30,22 +30,11 @@ export const codexProviderProfile: ProviderProfile = {
       openAiBeta: getInputHeader(input.baseHeaders, 'openai-beta')
         || (websocketTransport ? asTrimmedString(config.codexResponsesWebsocketBeta) : null),
     });
-    const codexSessionId = getInputHeader(headers, 'session_id') || getInputHeader(headers, 'session-id');
-    const shouldInjectDerivedPromptCacheKey = !!codexSessionId
-      && !asTrimmedString(input.body.prompt_cache_key)
-      && !asTrimmedString(input.codexExplicitSessionId)
-      && !!asTrimmedString(input.codexSessionCacheKey);
-    const body = shouldInjectDerivedPromptCacheKey
-      ? {
-        ...input.body,
-        prompt_cache_key: codexSessionId,
-      }
-      : input.body;
 
     return {
       path: '/responses',
       headers,
-      body,
+      body: input.body,
       runtime: {
         executor: 'codex',
         modelName: input.modelName,

src/server/proxy-core/providers/registry.test.ts

@@ -39,7 +39,11 @@ describe('resolveProviderProfile', () => {
       modelName: 'gpt-5.2-codex',
       stream: true,
     });
-    expect(result.body.prompt_cache_key).toBe(result.headers.Session_id);
+    expect(result.body).toEqual({
+      model: 'gpt-5.2-codex',
+      stream: true,
+      store: false,
+    });
   });
 
   it('builds claude provider requests without rebuilding protocol bodies', () => {