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/backend/package.json

@@ -31,6 +31,7 @@
     "nanoid": "^3.3.11",
     "nodemailer": "^7.0.3",
     "pg": "^8.16.0",
+    "sharp": "^0.33.5",
     "slugify": "^1.6.6",
     "uuid": "^11.1.0"
   },
@@ -38,6 +39,7 @@
     "@types/fluent-ffmpeg": "^2.1.27",
     "@types/nodemailer": "^6.4.17",
     "@types/pg": "^8.15.4",
+    "@types/sharp": "^0.32.0",
     "@types/uuid": "^10.0.0",
     "drizzle-kit": "^0.31.1",
     "tsx": "^4.19.4",