feat(数据库): 添加提示词优化历史表

- 新增 prompt_optimizations 表存储用户的提示词优化历史
- 支持记录原始提示词、优化后提示词和优化模式
- 添加相应的数据库迁移文件

src/drizzle/migrations/0009_omniscient_vision.sql

@@ -0,0 +1,10 @@
+CREATE TABLE "prompt_optimizations" (
+	"id" serial PRIMARY KEY NOT NULL,
+	"user_id" varchar(64) NOT NULL,
+	"original_prompt" text NOT NULL,
+	"optimized_prompt" text NOT NULL,
+	"mode" varchar(20) NOT NULL,
+	"created_at" timestamp with time zone DEFAULT now()
+);
+--> statement-breakpoint
+ALTER TABLE "user_settings" ALTER COLUMN "default_model" SET DEFAULT 'claude-sonnet-4-5-20250929';

src/drizzle/migrations/meta/_journal.json

@@ -64,6 +64,13 @@
       "when": 1766314954003,
       "tag": "0008_flat_star_brand",
       "breakpoints": true
+    },
+    {
+      "idx": 9,
+      "version": "7",
+      "when": 1766323563111,
+      "tag": "0009_omniscient_vision",
+      "breakpoints": true
     }
   ]
 }

src/drizzle/schema.ts

@@ -289,6 +289,23 @@ export const notes = pgTable('notes', {
   updatedAt: timestamp('updated_at', { withTimezone: true }).defaultNow(),
 });
 
+// ============================================
+// 提示词优化历史表
+// ============================================
+export const promptOptimizations = pgTable('prompt_optimizations', {
+  id: serial('id').primaryKey(),
+  // 关联用户
+  userId: varchar('user_id', { length: 64 }).notNull(),
+  // 原始提示词
+  originalPrompt: text('original_prompt').notNull(),
+  // 优化后的提示词
+  optimizedPrompt: text('optimized_prompt').notNull(),
+  // 优化模式: concise(简洁版) | detailed(详细版)
+  mode: varchar('mode', { length: 20 }).notNull(),
+  // 时间戳
+  createdAt: timestamp('created_at', { withTimezone: true }).defaultNow(),
+});
+
 // ============================================
 // 关系定义
 // ============================================
@@ -431,3 +448,6 @@ export type NewUserFavoriteAssistant = typeof userFavoriteAssistants.$inferInser
 
 export type Note = typeof notes.$inferSelect;
 export type NewNote = typeof notes.$inferInsert;
+
+export type PromptOptimization = typeof promptOptimizations.$inferSelect;
+export type NewPromptOptimization = typeof promptOptimizations.$inferInsert;