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/internal/gallery/media_test.go

@@ -12,6 +12,15 @@ func TestVideoPosterRel(t *testing.T) {
 	}
 }
 
+func TestIsWebDerivative(t *testing.T) {
+	if !isWebDerivative("clip.web.mp4") {
+		t.Fatal("expected web derivative")
+	}
+	if isGalleryMedia("clip.web.mp4") {
+		t.Fatal("web derivative must not be listed")
+	}
+}
+
 func TestList_includesVideo(t *testing.T) {
 	dir := t.TempDir()
 	album := filepath.Join(dir, "portal")