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.

apps/web/src/app/api/docs/[id]/route.ts

@@ -0,0 +1,20 @@
+import { NextResponse } from "next/server";
+import { getRedis } from "@/lib/redis";
+
+export async function GET(
+  _request: Request,
+  { params }: { params: Promise<{ id: string }> }
+) {
+  const { id } = await params;
+  const redis = getRedis();
+
+  const result = await redis.get(`codeboard:result:${id}`);
+  if (!result) {
+    return NextResponse.json(
+      { error: "Documentation not found" },
+      { status: 404 }
+    );
+  }
+
+  return NextResponse.json(JSON.parse(result));
+}