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/+page.svelte

@@ -144,7 +144,7 @@ const { data } = $props();
             <div
               class="absolute bottom-2 left-2 text-white text-sm font-medium"
             >
-              {formatVideoDuration(video.movie.duration)}
+              {#if video.movie_file?.duration}{formatVideoDuration(video.movie_file.duration)}{/if}
             </div>
             <!-- <div
               class="absolute top-2 right-2 bg-black/50 text-white text-xs px-2 py-1 rounded-full"