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.

.dockerignore

@@ -0,0 +1,7 @@
+node_modules
+.next
+.git
+data
+*.env
+!.env.example
+*.tsbuildinfo