Filter non-browser-playable formats from Doom Scroll

Formats like .mkv, .avi, .wmv, .ts, .m2ts and .tiff are not natively
supported by browsers and would stall silently in Doom Scroll mode.

Add src/lib/browser-media.ts with BROWSER_VIDEO_EXTENSIONS (.mp4,
.webm, .mov, .m4v), BROWSER_IMAGE_EXTENSIONS (.jpg, .jpeg, .png, .gif,
.webp, .bmp), and an isBrowserPlayable() helper that extracts the
extension without importing Node's path module.

Filter doomScrollItems in MixedView, MoviesView, and TvView using this
helper so only natively renderable files are passed to DoomScrollView.

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

src/components/movies/MoviesView.tsx

@@ -5,6 +5,7 @@ import type { Movie } from '@/types'
 import MovieDetailModal from './MovieDetailModal'
 import FilterPanel from '@/components/FilterPanel'
 import DoomScrollView, { type DoomScrollItem } from '@/components/DoomScrollView'
+import { isBrowserPlayable } from '@/lib/browser-media'
 
 interface Props {
   libraryId: string
@@ -74,7 +75,7 @@ export default function MoviesView({ libraryId }: Props) {
 
   const handleDoomScroll = () => {
     // Use filtered movies — respects any active search/tag filters automatically
-    const items: DoomScrollItem[] = filtered.map((m) => ({
+    const items: DoomScrollItem[] = filtered.filter((m) => isBrowserPlayable(m.videoPath)).map((m) => ({
       url: `/api/file?libraryId=${encodeURIComponent(libraryId)}&path=${encodeURIComponent(m.videoPath)}`,
       name: m.title,
       mediaType: 'video' as const,