feat: initial monorepo scaffold - Next.js 15 + Prisma + Python SDK stubs

- Turborepo monorepo with apps/web and packages/database, sdk-python
- Next.js 15 app with professional landing page (dark theme, emerald accent)
- Prisma schema: Trace, DecisionPoint, Span, Event models with full indexing
- Docker Compose: web (port 4200), postgres:16, redis:7, migrate service
- Python SDK package stubs: init, trace decorator, log_decision, integrations
- Multi-stage Dockerfile for standalone Next.js production build

docker-compose.yml

@@ -0,0 +1,55 @@
+services:
+  web:
+    build:
+      context: .
+      target: web
+    ports:
+      - "4200:3000"
+    environment:
+      - REDIS_URL=redis://redis:6379
+      - DATABASE_URL=postgresql://agentlens:agentlens@postgres:5432/agentlens
+    depends_on:
+      redis:
+        condition: service_started
+      postgres:
+        condition: service_healthy
+      migrate:
+        condition: service_completed_successfully
+    restart: always
+
+  postgres:
+    image: postgres:16-alpine
+    environment:
+      - POSTGRES_USER=agentlens
+      - POSTGRES_PASSWORD=agentlens
+      - POSTGRES_DB=agentlens
+    volumes:
+      - agentlens_postgres_data:/var/lib/postgresql/data
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U agentlens"]
+      interval: 5s
+      timeout: 5s
+      retries: 5
+    restart: always
+
+  migrate:
+    build:
+      context: .
+      target: builder
+    command: npx prisma migrate deploy --schema=packages/database/prisma/schema.prisma
+    environment:
+      - DATABASE_URL=postgresql://agentlens:agentlens@postgres:5432/agentlens
+    depends_on:
+      postgres:
+        condition: service_healthy
+    restart: "no"
+
+  redis:
+    image: redis:7-alpine
+    volumes:
+      - agentlens_redis_data:/data
+    restart: always
+
+volumes:
+  agentlens_postgres_data:
+  agentlens_redis_data: