feat: brain-engine + brain-ui + docs — template full stack standalone

- brain-engine: server, embed, search, RAG, MCP, start.sh (standalone)
- brain-ui: source React complète, build.sh, DocsView avec tier colors
- docs: 14 pages guides humains (getting-started, architecture, sessions, workflows, agents, vues tier)
- brain-compose.yml v0.9.0: tier featured ajouté, sessions/agents par tier, coach_level, API key schema
- DISTRIBUTION_CHECKLIST v1.2: brain-engine + brain-ui + docs dans la checklist

brain-ui/package.json

@@ -0,0 +1,34 @@
+{
+  "name": "brain-ui",
+  "version": "0.1.0",
+  "private": true,
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "tsc && vite build",
+    "preview": "vite preview"
+  },
+  "dependencies": {
+    "@react-three/drei": "^9.122.0",
+    "@react-three/fiber": "^8.18.0",
+    "@reactflow/core": "^11.11.4",
+    "lucide-react": "^0.454.0",
+    "react": "^18.3.1",
+    "react-dom": "^18.3.1",
+    "react-markdown": "^10.1.0",
+    "reactflow": "^11.11.4",
+    "three": "^0.163.0",
+    "zustand": "^5.0.12"
+  },
+  "devDependencies": {
+    "@types/react": "^18.3.12",
+    "@types/react-dom": "^18.3.1",
+    "@types/three": "^0.163.0",
+    "@vitejs/plugin-react": "^4.3.3",
+    "autoprefixer": "^10.4.20",
+    "postcss": "^8.4.47",
+    "tailwindcss": "^3.4.14",
+    "typescript": "^5.6.3",
+    "vite": "^5.4.10"
+  }
+}