fix(deploy): configurable postgres host port (avoid 5432 conflict)

fr2-postgres failed to start after another local project's postgres grabbed host
port 5432 during downtime. The internal stack always connects via postgres:5432 on
the docker network, so the published host port is only for external tooling — make
it ${PG_HOST_PORT:-5532} to avoid the clash. (Also recovered from a stale bind-mount
where scripts/init-db.sh had become a directory; current compose mounts
deploy/postgres-initdb/.)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docker-compose.v2.yml

@@ -32,7 +32,9 @@ services:
     ports:
       # HOST_BIND=127.0.0.1 in prod keeps these off the public interface (only
       # Caddy's 80/443 face the internet). Unset → 0.0.0.0 for local/LAN dev.
-      - "${HOST_BIND:-0.0.0.0}:5432:5432"
+      # Host port is configurable (PG_HOST_PORT) — 5432 is often taken by another
+      # local project's postgres; the internal stack always uses postgres:5432.
+      - "${HOST_BIND:-0.0.0.0}:${PG_HOST_PORT:-5532}:5432"
     healthcheck:
       test: ["CMD-SHELL", "pg_isready -U ${POSTGRES_USER:-postgres} -d flatrender"]
       interval: 5s