feat: build an AI agent from 0 to 1 -- 11 progressive sessions

- 11 sessions from basic agent loop to autonomous teams
- Python MVP implementations for each session
- Mental-model-first docs in en/zh/ja
- Interactive web platform with step-through visualizations
- Incremental architecture: each session adds one mechanism

web/vercel.json

@@ -0,0 +1,9 @@
+{
+  "redirects": [
+    {
+      "source": "/",
+      "destination": "/en",
+      "permanent": false
+    }
+  ]
+}