feat: initial CodeBoard monorepo scaffold

Turborepo monorepo with npm workspaces:
- apps/web: Next.js 14 frontend with Tailwind v4, SSE progress, doc viewer
- apps/worker: BullMQ job processor (clone → parse → LLM generate)
- packages/shared: TypeScript types
- packages/parser: Babel-based AST parser (JS/TS) + regex (Python)
- packages/llm: OpenAI/Anthropic provider abstraction + prompt pipeline
- packages/diagrams: Mermaid architecture & dependency graph generators
- packages/database: Prisma schema (PostgreSQL)
- Docker multi-stage build (web + worker targets)

All packages compile successfully with tsc and next build.

packages/database/package.json

@@ -0,0 +1,24 @@
+{
+  "name": "@codeboard/database",
+  "version": "0.0.1",
+  "private": true,
+  "main": "./src/client.ts",
+  "types": "./src/client.ts",
+  "exports": {
+    ".": "./src/client.ts"
+  },
+  "scripts": {
+    "build": "echo 'database package uses prisma generate'",
+    "db:generate": "prisma generate",
+    "db:push": "prisma db push",
+    "db:migrate": "prisma migrate dev",
+    "clean": "rm -rf generated"
+  },
+  "dependencies": {
+    "@prisma/client": "^6.3.0"
+  },
+  "devDependencies": {
+    "prisma": "^6.3.0",
+    "typescript": "^5.7"
+  }
+}