Add gallery admin and video media support.

This updates gallery handling to support video playback with generated poster thumbnails, adds authenticated admin upload/delete flows, and improves dev/runtime behavior including reliable thumbnail generation and media-safe response handling.

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

app/templates/gallery.templ

@@ -31,6 +31,9 @@ templ GalleryGrid(images []gallery.Image) {
 				} else {
 					<span class="gallery-placeholder" aria-hidden="true"></span>
 				}
+				if img.IsVideo {
+					<span class="gallery-video-badge" aria-hidden="true">Video</span>
+				}
 				if img.Collection != "" {
 					<span class="gallery-album">{ img.Collection }</span>
 				} else if img.Album != "" {
@@ -49,7 +52,7 @@ templ ImageModal(img gallery.Image, prevPath, nextPath string) {
 		class="modal-backdrop"
 		hx-on:click="if (event.target === this) this.remove()"
 	>
-		<div class="modal" role="dialog" aria-modal="true" aria-label="Image viewer">
+		<div class="modal" role="dialog" aria-modal="true" aria-label={ modalAriaLabel(img) }>
 			<button
 				type="button"
 				class="modal-close"
@@ -59,7 +62,11 @@ templ ImageModal(img gallery.Image, prevPath, nextPath string) {
 				&times;
 			</button>
 			<figure class="modal-figure">
-				<img src={ img.URL } alt={ img.Filename }/>
+				if img.IsVideo {
+					<video src={ img.URL } controls playsinline preload="metadata"></video>
+				} else {
+					<img src={ img.URL } alt={ img.Filename }/>
+				}
 				if !img.Date.IsZero() {
 					<figcaption>{ modalCaption(img) }</figcaption>
 				}
@@ -98,7 +105,14 @@ func formatDate(t time.Time) string {
 	if t.IsZero() {
 		return ""
 	}
-	return t.Format("2 Jan 2006")
+	return t.Format("Jan 2006")
+}
+
+func modalAriaLabel(img gallery.Image) string {
+	if img.IsVideo {
+		return "Video viewer"
+	}
+	return "Image viewer"
 }
 
 func modalCaption(img gallery.Image) string {