feat(design): add infrastructure diagram

design.md

@@ -94,19 +94,46 @@ Notes:
 Describe the deployment strategy and infrastructure requirements.
 
 - Environments: prod, local dev
-- Runtime platform: Kubernetes
+- Runtime platform: Kubernetes, serverless - cloudflare pages
 - Infrastructure diagram (optional):
 
 ```mermaid
 flowchart TB
-  subgraph Cloud
-    lb[Load Balancer]
-    asg[Service / Deployment]
-    db[(Managed DB)]
-    bucket[(Object Storage)]
-  end
-  user((User)) --> lb --> asg --> db
-  asg --> bucket
+    subgraph "Cloudflare"
+        pages[React App<br/>Cloudflare Pages]
+    end
+    
+    subgraph "Kubernetes Cluster"
+        subgraph "Ingress"
+            ingress[Ingress Controller]
+        end
+        
+        subgraph "Services"
+            api[API Gateway /<br/>Web Server]
+            svc[Web API Service]
+            worker[Worker Service]
+            planner[Task Planner]
+        end
+        
+        subgraph "Infrastructure"
+            queue[Message Queue]
+            db[(Database)]
+            cache[(Cache)]
+        end
+    end
+    
+    user((User)) --> pages
+    pages -.-> ingress
+    ingress --> api
+    api --> svc
+    svc --> queue
+    svc --> db
+    svc --> cache
+    
+    queue --> worker
+    planner --> queue
+    
+    worker --> db
 ```
 
 - Configuration & secrets: Env vars, secret manager, .env files (never commit secrets).