Aggiungo stack Supabase self-hosted e config di produzione

Stack Docker completo in infra/supabase/docker/ (vendored da supabase/supabase)
per svincolare dev e produzione da Lovable Cloud. Include override di
produzione che non espone porte pubblicamente e disattiva i servizi non
usati da CrAPP (Realtime, Storage, imgproxy, Edge Functions, pooler),
un Caddyfile con routing /api/* per un solo dominio, e i template .env
per app e stack. Forzo inoltre il preset Nitro a node-server in
vite.config.ts, dato che il default sarebbe Cloudflare Workers.

infra/supabase/docker/docker-compose.pg17.yml

@@ -0,0 +1,19 @@
+# Postgres 17 override for self-hosted Supabase.
+#
+# NOTE: Postgres 17 is now the default in docker-compose.yml, so this override
+# is redundant for new installs (kept for explicitness / backwards compatibility).
+# Keep the image tag here in sync with the db image in docker-compose.yml.
+#
+# Usage (new install or after upgrade):
+#   docker compose -f docker-compose.yml -f docker-compose.pg17.yml up -d
+#
+# For upgrading an existing Postgres 15 database, run utils/upgrade-pg17.sh first.
+#
+# Note: PG 15 and PG 17 use different postgres UIDs. If starting fresh with a
+# leftover db-config volume from PG 15, you may see
+# "FATAL: invalid secret key". Either remove the old volume or fix ownership.
+# See: docs/guides/self-hosting/postgres-upgrade-17
+
+services:
+  db:
+    image: supabase/postgres:17.6.1.136