Add Docker Compose deployment

Full node_modules image (not output: standalone — its file-tracing drops
argon2's JS loader and segfaults in prod). drizzle.config.ts now honors
DATA_DIR like the sibling projects, so db:migrate targets the mounted
volume instead of an image-local path.

drizzle.config.ts

@@ -1,10 +1,13 @@
 import { defineConfig } from "drizzle-kit";
+import path from "node:path";
+
+const dataDir = process.env.DATA_DIR ?? path.join(process.cwd(), "data");
 
 export default defineConfig({
   out: "./src/lib/db/migrations",
   schema: "./src/lib/db/schema.ts",
   dialect: "sqlite",
   dbCredentials: {
-    url: "./data/db.sqlite",
+    url: path.join(dataDir, "db.sqlite"),
   },
 });