feat: add utoipa path annotations to all API handlers and wire OpenAPI spec

- Add #[utoipa::path] annotations to all 70+ handler functions across
  auth, config, workflow, and message modules
- Add IntoParams/ToSchema derives to Pagination, PaginatedResponse, ApiResponse
  in erp-core, and MessageQuery/TemplateQuery in erp-message
- Collect all module paths into OpenAPI spec via AuthApiDoc, ConfigApiDoc,
  WorkflowApiDoc, MessageApiDoc structs in erp-server main.rs
- Update openapi_spec handler to merge all module specs
- The /docs/openapi.json endpoint now returns complete API documentation
  with all endpoints, request/response schemas, and security requirements

crates/erp-config/src/handler/theme_handler.rs

@@ -10,6 +10,17 @@ use crate::config_state::ConfigState;
 use crate::dto::{SetSettingParams, ThemeResp};
 use crate::service::setting_service::SettingService;
 
+#[utoipa::path(
+    get,
+    path = "/api/v1/themes",
+    responses(
+        (status = 200, description = "成功", body = ApiResponse<ThemeResp>),
+        (status = 401, description = "未授权"),
+        (status = 403, description = "权限不足"),
+    ),
+    security(("bearer_auth" = [])),
+    tag = "主题设置"
+)]
 /// GET /api/v1/theme
 ///
 /// 获取当前租户的主题配置。
@@ -33,6 +44,18 @@ where
     Ok(JsonResponse(ApiResponse::ok(theme)))
 }
 
+#[utoipa::path(
+    put,
+    path = "/api/v1/themes",
+    request_body = ThemeResp,
+    responses(
+        (status = 200, description = "成功", body = ApiResponse<ThemeResp>),
+        (status = 401, description = "未授权"),
+        (status = 403, description = "权限不足"),
+    ),
+    security(("bearer_auth" = [])),
+    tag = "主题设置"
+)]
 /// PUT /api/v1/theme
 ///
 /// 更新当前租户的主题配置。