[codex] Remove Codex SDK canary runtime (#220)

* Revert "fix: drain sdk follow-up turns (#219)"

This reverts commit 807828e0ce.

* Revert "feat: feature-flag Codex SDK runner (#218)"

This reverts commit 879d16235f.

src/agent-runner.test.ts

@@ -852,53 +852,4 @@ describe('agent-runner Codex goals', () => {
       | undefined;
     expect(spawnEnv?.CODEX_GOALS).toBe('true');
   });
-
-  it('marks SDK codex processes so queued IPC follow-ups drain after the active run', async () => {
-    const previousCodexGoals = process.env.CODEX_GOALS;
-    delete process.env.CODEX_GOALS;
-    const onProcess = vi.fn();
-    const codexGroup: RegisteredGroup = {
-      ...testGroup,
-      agentType: 'codex',
-    };
-
-    try {
-      const resultPromise = runAgentProcess(
-        codexGroup,
-        {
-          ...testInput,
-          roomRoleContext: {
-            serviceId: 'codex-main',
-            role: 'owner',
-            ownerServiceId: 'codex-main',
-            reviewerServiceId: 'claude',
-            failoverOwner: false,
-          },
-        },
-        onProcess,
-        async () => {},
-        {
-          CODEX_RUNTIME: 'sdk',
-          CODEX_RUNTIME_SDK_ROLES: 'owner',
-        },
-      );
-
-      fakeProc.emit('close', 0);
-      const result = await resultPromise;
-      expect(result.status).toBe('success');
-
-      expect(onProcess).toHaveBeenCalledWith(
-        fakeProc,
-        expect.any(String),
-        expect.any(String),
-        { drainFollowUpsAfterRun: true },
-      );
-    } finally {
-      if (previousCodexGoals === undefined) {
-        delete process.env.CODEX_GOALS;
-      } else {
-        process.env.CODEX_GOALS = previousCodexGoals;
-      }
-    }
-  });
 });