feat: update AI subject generation and handling responses

- Refactor AIGenerateSubjectInput type to include optional fields for updates.
- Add handling for "asignaturas" responses in OpenAI webhook.
- Implement crear.ts for creating/updating subjects based on AI responses.
- Update tests to validate OpenAI file uploads instead of storage uploads.

supabase/functions/tests/ai-generate-test-prototipo.ts

@@ -141,7 +141,7 @@ Deno.test("ai-structured (multipart + file)", async () => {
   assert(typeof data.output?.resumen === "string");
   assert(data.output.resumen.length > 0);
 
-  // opcional: valida que registró upload(s) a storage
-  assert(Array.isArray(data.references?.uploadedToStorage));
+    // opcional: valida que registró upload(s) a OpenAI files
+    assert(Array.isArray(data.references?.openaiFileIds));
 });
  */

supabase/functions/tests/ai-structured-test.ts

@@ -160,6 +160,6 @@ Deno.test({
   assert(typeof data.output?.resumen === "string");
   assert(data.output.resumen.length > 0);
 
-  // opcional: valida que registró upload(s) a storage
-  assert(Array.isArray(data.references?.uploadedToStorage));
+  // opcional: valida que registró upload(s) a OpenAI files
+  assert(Array.isArray(data.references?.openaiFileIds));
 });