Add photo galleries API and frontend for public and admin viewing.

Introduces the Go photo-api service, nginx/systemd deploy wiring, and Next.js gallery/lightbox pages so event photos can be managed and browsed.

Co-authored-by: Cursor <cursoragent@cursor.com>

photo-api/Makefile

@@ -0,0 +1,23 @@
+.PHONY: start build test migrate clean help
+
+BINARY := bin/photo-api
+CMD    := ./cmd/photo-api
+
+help: ## Show available targets
+	@grep -E '^[a-zA-Z_-]+:.*?##' $(MAKEFILE_LIST) | \
+		awk 'BEGIN {FS = ":.*?## "}; {printf "  %-12s %s\n", $$1, $$2}'
+
+start: ## Run the photo-api server (go run)
+	go run $(CMD)
+
+build: ## Build binary to bin/photo-api
+	go build -o $(BINARY) $(CMD)
+
+test: ## Run all Go tests
+	go test ./...
+
+migrate: ## Apply pending photos_* migrations
+	go run $(CMD) migrate
+
+clean: ## Remove built binary
+	rm -rf bin