Add Compose stack & Caddy deploy artifacts (task 05)

Multi-stage Dockerfile (pnpm fetch/offline, standalone output, non-root
nextjs user), deploy/compose.yaml with famapp + famapp-db + full Authentik
stack on famapp_net, Caddyfile.snippet for fam/auth.ginnoir.com, and
.env.production.example. Added .dockerignore and public/.gitkeep.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.dockerignore

@@ -0,0 +1,10 @@
+node_modules
+.next
+.git
+deploy
+drizzle
+docs
+*.md
+.env*
+!.env.example
+.vscode