feat: add codex provider via Responses API

src/services/api/codex/__tests__/preflight.test.ts

@@ -0,0 +1,51 @@
+import { describe, expect, test } from 'bun:test'
+import { sanitizeCodexRequest } from '../preflight.js'
+
+describe('sanitizeCodexRequest', () => {
+  test('normalizes function call ids and tool names', () => {
+    const request = sanitizeCodexRequest({
+      model: 'gpt-5.4',
+      input: [
+        {
+          type: 'function_call',
+          call_id: ' tool 1 / weird ',
+          name: ' Read ',
+          arguments: '{}',
+        },
+      ] as any,
+      tools: [
+        {
+          type: 'function',
+          name: ' Read ',
+          parameters: null,
+        },
+      ] as any,
+    } as any)
+
+    expect(request.input?.[0]).toMatchObject({
+      type: 'function_call',
+      call_id: 'tool_1_weird',
+      name: 'Read',
+    })
+    expect(request.tools?.[0]).toMatchObject({
+      type: 'function',
+      name: 'Read',
+      parameters: {},
+    })
+  })
+
+  test('rejects invalid function_call_output without call_id', () => {
+    expect(() =>
+      sanitizeCodexRequest({
+        model: 'gpt-5.4',
+        input: [
+          {
+            type: 'function_call_output',
+            call_id: '   ',
+            output: 'ok',
+          },
+        ] as any,
+      } as any),
+    ).toThrow('Codex preflight: function_call_output.call_id is required.')
+  })
+})