feat: add git hooks for pre-push validation and post-merge auto-deploy

- .githooks/pre-push: validate Pd patches via python3 pd-validator
- .githooks/post-merge: auto-restart services when systemd/scripts change
- install.sh: configure core.hooksPath at install time
- justfile deploy: set hooksPath after git pull

install.sh

@@ -27,4 +27,7 @@ for svc in "${SERVICES[@]}"; do
     sudo systemctl enable "$svc"
 done
 
+# Install git hooks: point to repo's .githooks so post-merge auto-restarts services
+git config core.hooksPath "$REPO/.githooks"
+
 echo "[OK] Services installed and enabled"