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

packages/database/package.json

@@ -0,0 +1,21 @@
+{
+  "name": "@agentlens/database",
+  "version": "0.0.1",
+  "private": true,
+  "main": "./dist/index.js",
+  "types": "./dist/index.d.ts",
+  "scripts": {
+    "build": "tsc",
+    "clean": "rm -rf dist",
+    "db:generate": "prisma generate",
+    "db:push": "prisma db push",
+    "db:migrate": "prisma migrate dev"
+  },
+  "dependencies": {
+    "@prisma/client": "^6.3.0"
+  },
+  "devDependencies": {
+    "prisma": "^6.3.0",
+    "typescript": "^5.7"
+  }
+}

packages/database/prisma/schema.prisma

@@ -0,0 +1,154 @@
+datasource db {
+  provider = "postgresql"
+  url      = env("DATABASE_URL")
+}
+
+generator client {
+  provider = "prisma-client-js"
+}
+
+model Trace {
+  id          String   @id @default(cuid())
+  sessionId   String?
+  name        String
+  status      TraceStatus @default(RUNNING)
+  tags        String[] @default([])
+  metadata    Json?
+
+  totalCost     Float?
+  totalTokens   Int?
+  totalDuration Int?
+
+  startedAt   DateTime @default(now())
+  endedAt     DateTime?
+  createdAt   DateTime @default(now())
+  updatedAt   DateTime @updatedAt
+
+  decisionPoints DecisionPoint[]
+  spans          Span[]
+  events         Event[]
+
+  @@index([sessionId])
+  @@index([status])
+  @@index([createdAt])
+  @@index([name])
+}
+
+model DecisionPoint {
+  id          String   @id @default(cuid())
+  traceId     String
+  trace       Trace    @relation(fields: [traceId], references: [id], onDelete: Cascade)
+
+  type        DecisionType
+  reasoning   String?
+
+  chosen      Json
+  alternatives Json[]
+
+  contextSnapshot Json?
+
+  durationMs  Int?
+  costUsd     Float?
+
+  parentSpanId String?
+  span        Span?    @relation(fields: [parentSpanId], references: [id])
+
+  timestamp   DateTime @default(now())
+
+  @@index([traceId])
+  @@index([type])
+  @@index([timestamp])
+}
+
+model Span {
+  id          String   @id @default(cuid())
+  traceId     String
+  trace       Trace    @relation(fields: [traceId], references: [id], onDelete: Cascade)
+
+  parentSpanId String?
+  parentSpan   Span?   @relation("SpanTree", fields: [parentSpanId], references: [id])
+  childSpans   Span[]  @relation("SpanTree")
+
+  name        String
+  type        SpanType
+
+  input       Json?
+  output      Json?
+
+  tokenCount  Int?
+  costUsd     Float?
+  durationMs  Int?
+
+  status      SpanStatus @default(RUNNING)
+  statusMessage String?
+
+  startedAt   DateTime @default(now())
+  endedAt     DateTime?
+
+  metadata    Json?
+
+  decisionPoints DecisionPoint[]
+
+  @@index([traceId])
+  @@index([parentSpanId])
+  @@index([type])
+  @@index([startedAt])
+}
+
+model Event {
+  id          String   @id @default(cuid())
+  traceId     String
+  trace       Trace    @relation(fields: [traceId], references: [id], onDelete: Cascade)
+
+  spanId      String?
+  type        EventType
+  name        String
+
+  metadata    Json?
+
+  timestamp   DateTime @default(now())
+
+  @@index([traceId])
+  @@index([type])
+  @@index([timestamp])
+}
+
+enum TraceStatus {
+  RUNNING
+  COMPLETED
+  ERROR
+}
+
+enum DecisionType {
+  TOOL_SELECTION
+  ROUTING
+  RETRY
+  ESCALATION
+  MEMORY_RETRIEVAL
+  PLANNING
+  CUSTOM
+}
+
+enum SpanType {
+  LLM_CALL
+  TOOL_CALL
+  MEMORY_OP
+  CHAIN
+  AGENT
+  CUSTOM
+}
+
+enum SpanStatus {
+  RUNNING
+  COMPLETED
+  ERROR
+}
+
+enum EventType {
+  ERROR
+  RETRY
+  FALLBACK
+  CONTEXT_OVERFLOW
+  USER_FEEDBACK
+  CUSTOM
+}

packages/database/src/index.ts

@@ -0,0 +1,2 @@
+export { PrismaClient } from "@prisma/client";
+export type * from "@prisma/client";

packages/database/tsconfig.json

@@ -0,0 +1,18 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "NodeNext",
+    "moduleResolution": "NodeNext",
+    "lib": ["ES2022"],
+    "outDir": "./dist",
+    "rootDir": "./src",
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "declaration": true,
+    "declarationMap": true,
+    "sourceMap": true
+  },
+  "include": ["src/**/*"],
+  "exclude": ["node_modules", "dist"]
+}