feat: 统一 JSON API 到 /v1 前缀，移除旧邮件兼容路由

- 删除旧邮件查询兼容路由 GET /mail-api/messages、/mail-api/messages/{id}、/mail-api/search
- 所有 JSON API 统一使用 /v1/...：邮件、上下文记忆、动态页面创建和健康检查接口
- 页面路由保持非 /v1 地址：/mail、/mail/messages/{id}、/mail/{slug}、/web/{page_type}/{slug}、/updates
- AI 内部工具调用同步改用 /v1/web/pages 与 /v1/context/memories...
- 无数据库结构变化，新增 0.1.14 升级日志记录

ias-context/src/routes.rs

@@ -29,10 +29,10 @@ where
     S: Clone + Send + Sync + 'static,
 {
     Router::new()
-        .route("/context/memories", post(create_memory))
-        .route("/context/memories/search", post(search_memories))
+        .route("/v1/context/memories", post(create_memory))
+        .route("/v1/context/memories/search", post(search_memories))
         .route(
-            "/context/memories/{id}",
+            "/v1/context/memories/{id}",
             patch(update_memory).delete(delete_memory),
         )
         .layer(Extension(ContextRouteState::new(db)))