feat: add question bank schema

Made-with: Cursor

src/db/schema/questionCacheMeta.ts

@@ -0,0 +1,18 @@
+import { pgTable, uuid, varchar, integer, timestamp } from 'drizzle-orm/pg-core';
+import { jsonb } from 'drizzle-orm/pg-core';
+import { questionBank } from './questionBank.js';
+
+export const questionCacheMeta = pgTable('question_cache_meta', {
+  id: uuid('id').primaryKey().defaultRandom(),
+  questionBankId: uuid('question_bank_id')
+    .notNull()
+    .references(() => questionBank.id, { onDelete: 'cascade' }),
+  llmModel: varchar('llm_model', { length: 100 }).notNull(),
+  promptHash: varchar('prompt_hash', { length: 64 }).notNull(),
+  generationTimeMs: integer('generation_time_ms').notNull(),
+  rawResponse: jsonb('raw_response').$type<unknown>(),
+  createdAt: timestamp('created_at', { withTimezone: true }).notNull().defaultNow(),
+});
+
+export type QuestionCacheMeta = typeof questionCacheMeta.$inferSelect;
+export type NewQuestionCacheMeta = typeof questionCacheMeta.$inferInsert;