Improve gallery video UX and add upload-to-publish media workflow.

Stage raw files in upload/, publish with make sync-media/publish, and polish the lightbox: autoplay, remembered volume, Escape to close, and image/video icons without poster or caption clutter.

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

app/cmd/server/main.go

@@ -22,7 +22,7 @@ func main() {
 		log.Fatal(err)
 	}
 
-	imagesDir := filepath.Join(root, "images")
+	imagesDir := envOr("IMAGES_DIR", filepath.Join(root, "images"))
 	staticDir := filepath.Join(root, "static")
 
 	if *thumbsOnly {
@@ -54,6 +54,7 @@ func main() {
 	srv.RegisterRoutes(mux)
 
 	addr := envOr("ADDR", ":8080")
+	log.Printf("gallery images: %s", imagesDir)
 	log.Printf("Technical Kiwi website listening on %s", addr)
 	if err := http.ListenAndServe(addr, middleware.Gzip(mux)); err != nil {
 		log.Fatal(err)