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

package.json

@@ -0,0 +1,20 @@
+{
+  "name": "agentlens",
+  "private": true,
+  "workspaces": ["apps/*", "packages/*"],
+  "scripts": {
+    "dev": "turbo dev",
+    "build": "turbo build",
+    "lint": "turbo lint",
+    "clean": "turbo clean",
+    "db:generate": "turbo db:generate",
+    "db:push": "turbo db:push",
+    "db:migrate": "turbo db:migrate"
+  },
+  "devDependencies": {
+    "turbo": "^2",
+    "typescript": "^5.7"
+  },
+  "engines": { "node": ">=20" },
+  "packageManager": "npm@10.8.2"
+}