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/worker/src/index.ts

@@ -0,0 +1,42 @@
+import { Worker } from "bullmq";
+import IORedis from "ioredis";
+import { processGenerationJob } from "./processor.js";
+
+const redisUrl = process.env.REDIS_URL ?? "redis://localhost:6379";
+const connection = new IORedis(redisUrl, { maxRetriesPerRequest: null });
+
+const worker = new Worker(
+  "codeboard:generate",
+  async (job) => {
+    console.log(`[worker] Processing job ${job.id}: ${job.data.repoUrl}`);
+    return processGenerationJob(job);
+  },
+  {
+    connection,
+    concurrency: 2,
+    removeOnComplete: { count: 100 },
+    removeOnFail: { count: 50 },
+  }
+);
+
+worker.on("completed", (job) => {
+  console.log(`[worker] Job ${job.id} completed`);
+});
+
+worker.on("failed", (job, err) => {
+  console.error(`[worker] Job ${job?.id} failed:`, err.message);
+});
+
+worker.on("ready", () => {
+  console.log("[worker] Ready and waiting for jobs on codeboard:generate");
+});
+
+async function shutdown() {
+  console.log("[worker] Shutting down...");
+  await worker.close();
+  await connection.quit();
+  process.exit(0);
+}
+
+process.on("SIGTERM", shutdown);
+process.on("SIGINT", shutdown);