feat: AI 助手模型管理（CRUD、会话绑定、自动化验收）

- Flyway V6：模型表、默认种子、ai_chat_session.model_id 回填
- 管理端 /api/admin/ai/models；用户端选模与新会话绑定
- 禁用模型后会话只读（5009）；chat 按会话 modelCode 调 DashScope
- 前端 AiModels 页、助手模型选择器与 localStorage
- 单测、AiModelManagementApiIT、Playwright E2E；e2e Profile 关闭注解限流
- 技术实施文档与验收报告；移除过期冲突分析文档

Co-authored-by: Cursor <cursoragent@cursor.com>

e2e/package.json

@@ -0,0 +1,13 @@
+{
+  "name": "jog-e2e",
+  "private": true,
+  "type": "module",
+  "scripts": {
+    "test": "playwright test",
+    "test:ui": "playwright test --ui",
+    "install:browsers": "playwright install chromium"
+  },
+  "devDependencies": {
+    "@playwright/test": "^1.49.1"
+  }
+}