refactor: 迁移脚本系统重构 + 新增 db 脚本 + 工作日志

- 清理全部旧迁移文件(0000-0011)和 meta 目录
- 使用 drizzle-kit generate 从 schema 重新生成单一迁移文件
  - 0000_perfect_pestilence.sql: 包含全部 49 张表
  - 修复 0011_ai_providers.sql 未在 journal 注册导致 migrate 失败的问题
  - 修复缺少 snapshot 文件的问题
  - 移除复杂 PREPARE/EXECUTE 条件 SQL,使用标准 CREATE TABLE
- package.json 新增脚本:
  - db:create: 创建数据库
  - db:push: 直接同步 schema(开发用)
  - db:setup: 一键 create → migrate → seed
- 干净数据库全流程测试通过: create → migrate → seed
- 更新工作日志(docs/work_log.md)

package.json

@@ -18,9 +18,12 @@
     "test:e2e": "playwright test",
     "test:e2e:smoke": "playwright test tests/e2e/smoke-auth.spec.ts",
     "test:e2e:full-routes": "playwright test tests/e2e/full-route-regression.spec.ts",
+    "db:create": "npx tsx scripts/create-db.ts",
     "db:seed": "npx tsx scripts/seed.ts",
     "db:generate": "drizzle-kit generate",
     "db:migrate": "drizzle-kit migrate",
+    "db:push": "drizzle-kit push",
+    "db:setup": "npx tsx scripts/create-db.ts && drizzle-kit migrate && npx tsx scripts/seed.ts",
     "audit": "npm audit --audit-level=moderate",
     "audit:report": "npm audit --json > audit-report.json",
     "backup": "bash scripts/backup-db.sh",