feat: add PostgreSQL persistence for permanent shareable links

- Add PostgreSQL service to docker-compose with health checks
- Add migrate service that runs prisma migrate deploy on startup
- Integrate Prisma client in worker: checks for existing generations
  (same repo+commit) before regenerating, writes to Postgres on completion
- Update /api/docs/[id] with Redis → PostgreSQL fallback + cache repopulation
- Update Dockerfile: prisma generate in build, copy Prisma engine to worker/web
- Add @codeboard/database dependency to web and worker packages
- Add initial SQL migration for Generation and User tables
- Change removeOnComplete to { age: 3600 } for job retention

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

@@ -1,5 +1,6 @@
 import { NextResponse } from "next/server";
 import { getRedis } from "@/lib/redis";
+import { prisma } from "@codeboard/database";
 
 export async function GET(
   _request: Request,
@@ -8,13 +9,34 @@ export async function GET(
   const { id } = await params;
   const redis = getRedis();
 
-  const result = await redis.get(`codeboard:result:${id}`);
-  if (!result) {
+  let result = await redis.get(`codeboard:result:${id}`);
+
+  if (result) {
+    return NextResponse.json(JSON.parse(result));
+  }
+
+  const generation = await prisma.generation.findFirst({
+    where: { id }
+  });
+
+  if (!generation || !generation.result) {
     return NextResponse.json(
       { error: "Documentation not found" },
       { status: 404 }
     );
   }
 
-  return NextResponse.json(JSON.parse(result));
+  const docs = generation.result as any;
+  docs.id = id;
+  docs.repoUrl = generation.repoUrl;
+  docs.repoName = generation.repoName;
+
+  await redis.set(
+    `codeboard:result:${id}`,
+    JSON.stringify(docs),
+    "EX",
+    86400
+  );
+
+  return NextResponse.json(docs);
 }