feat(session): integrate actix-web framework with enhanced session management

- Added actix-web and actix-multipart dependencies to Cargo.toml
- Integrated actix-web ResponseError trait for AppError handling
- Migrated session module to use actix-web request lifecycle management
- Enhanced Session struct with request-local state handling capabilities
- Implemented proper HTTP status code mapping for various error types
- Added comprehensive session middleware integration points
- Updated session state persistence and modification tracking logic
- Integrated proper JSON response formatting for error messages
- Added support for session renewal, purge, and unchanged state management

service/workspace/core.rs

@@ -541,6 +541,19 @@ impl WorkspaceService {
         .ok_or(AppError::NotFound("workspace not found".into()))
     }
 
+    pub(crate) async fn find_workspace_by_name(&self, name: &str) -> Result<Workspace, AppError> {
+        sqlx::query_as::<_, Workspace>(
+            "SELECT id, owner_id, name, description, avatar_url, visibility, plan, status, \
+             default_role, is_personal, archived_at, created_at, updated_at, deleted_at \
+             FROM workspace WHERE lower(name) = lower($1) AND deleted_at IS NULL",
+        )
+        .bind(name)
+        .fetch_optional(self.ctx.db.reader())
+        .await
+        .map_err(AppError::Database)?
+        .ok_or(AppError::NotFound("workspace not found".into()))
+    }
+
     pub async fn workspace_user_role(
         &self,
         user_uid: Uuid,