feat: Refactor code structure and optimize performance across multiple modules

mobile-apps/client-app/backend_architecture.mermaid

@@ -0,0 +1,27 @@
+flowchart TD
+    subgraph "Client"
+        A[Flutter App]
+    end
+
+    subgraph "Backend"
+        B[GraphQL Server (e.g., Node.js)]
+        C[Firebase]
+    end
+
+    subgraph "Firebase Services"
+        C1[Firebase Auth]
+        C2[Firebase Firestore]
+        C3[Firebase Storage]
+    end
+
+    A -- "GraphQL Queries/Mutations" --> B
+    A -- "Authentication" --> C1
+
+    B -- "Data Operations" --> C2
+    B -- "File Operations" --> C3
+
+    C1 -- "User Tokens" --> A
+    C2 -- "Data" --> B
+    C3 -- "Files" --> B
+
+    B -- "Data/Files" --> A