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-core/Cargo.toml

@@ -15,3 +15,4 @@ tracing.workspace = true
 axum.workspace = true
 sea-orm.workspace = true
 async-trait.workspace = true
+utoipa.workspace = true

crates/erp-core/src/types.rs

@@ -16,7 +16,7 @@ pub struct BaseFields {
 }
 
 /// 分页请求
-#[derive(Debug, Deserialize)]
+#[derive(Debug, Deserialize, utoipa::IntoParams)]
 pub struct Pagination {
     pub page: Option<u64>,
     pub page_size: Option<u64>,
@@ -120,7 +120,7 @@ mod tests {
 }
 
 /// 分页响应
-#[derive(Debug, Serialize)]
+#[derive(Debug, Serialize, utoipa::ToSchema)]
 pub struct PaginatedResponse<T> {
     pub data: Vec<T>,
     pub total: u64,
@@ -130,7 +130,7 @@ pub struct PaginatedResponse<T> {
 }
 
 /// API 统一响应
-#[derive(Debug, Serialize)]
+#[derive(Debug, Serialize, utoipa::ToSchema)]
 pub struct ApiResponse<T: Serialize> {
     pub success: bool,
     pub data: Option<T>,