fix: image transforms via Sharp, model photos crash, video duration

- Backend: add Sharp image transform endpoint (/assets/:id?transform=X)
  with presets: mini(64), thumbnail(200), preview(480), medium(960), banner(1280)
  Transformed images are cached as webp next to originals
- Frontend: fix model photos crash (p.directus_files_id → p)
- Frontend: fix model banner URL (data.model.banner.id → data.model.banner)
- Frontend: fix video duration display (video.movie.duration → video.movie_file?.duration)
  across models/[slug], videos, videos/[slug], and home pages

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/frontend/src/routes/videos/+page.svelte

@@ -34,11 +34,11 @@ const filteredVideos = $derived(() => {
 			const matchesCategory = categoryFilter === "all";
 			const matchesDuration =
 				durationFilter === "all" ||
-				(durationFilter === "short" && video.movie.duration < 10 * 60) ||
+				(durationFilter === "short" && (video.movie_file?.duration ?? 0) < 10 * 60) ||
 				(durationFilter === "medium" &&
-					video.movie.duration >= 10 * 60 &&
-					video.movie.duration < 20 * 60) ||
-				(durationFilter === "long" && video.movie.duration >= 20 * 60);
+					(video.movie_file?.duration ?? 0) >= 10 * 60 &&
+					(video.movie_file?.duration ?? 0) < 20 * 60) ||
+				(durationFilter === "long" && (video.movie_file?.duration ?? 0) >= 20 * 60);
 			return matchesSearch && matchesCategory && matchesDuration;
 		})
 		.sort((a, b) => {
@@ -50,7 +50,7 @@ const filteredVideos = $derived(() => {
 				return (b.likes_count || 0) - (a.likes_count || 0);
 			if (sortBy === "most_played")
 				return (b.plays_count || 0) - (a.plays_count || 0);
-			if (sortBy === "duration") return b.movie.duration - a.movie.duration;
+			if (sortBy === "duration") return (b.movie_file?.duration ?? 0) - (a.movie_file?.duration ?? 0);
 			return a.title.localeCompare(b.title);
 		});
 });
@@ -220,7 +220,7 @@ const filteredVideos = $derived(() => {
             <div
               class="absolute bottom-3 left-3 bg-black/70 text-white text-sm px-2 py-1 rounded font-medium"
             >
-              {formatVideoDuration(video.movie.duration)}
+              {#if video.movie_file?.duration}{formatVideoDuration(video.movie_file.duration)}{/if}
             </div>
 
             <!-- Premium Badge -->

packages/frontend/src/routes/videos/[slug]/+page.svelte

@@ -221,7 +221,7 @@ let showPlayer = $state(false);
               <div
                 class="absolute bottom-4 left-4 bg-black/70 text-white px-3 py-1 rounded font-medium"
               >
-                {formatVideoDuration(data.video.movie.duration)}
+                {#if data.video.movie_file?.duration}{formatVideoDuration(data.video.movie_file.duration)}{/if}
               </div>
               {#if data.video.premium}
                 <div