feat(embeds): fullscreen, wider cards, Instagram/Tidal/Reddit; fix TikTok/X/Twitch

Feedback fixes + new platforms:
- Fullscreen: add a universal 'Fullscreen' button on video embeds (requests
  fullscreen on the media container) so Shorts/TikTok/etc. can go fullscreen
  regardless of each player's own controls. Portrait media enlarged (220->300).
- Drop the iframe sandbox (CSP-allowlisted trusted hosts; sandbox was breaking
  player features and likely TikTok).
- Wider, responsive embed/tweet cards (min(34rem,92vw)) so Twitch player chrome
  isn't cramped and X posts stop getting clipped.
- Instagram (p/reel/tv), Tidal (track/album/playlist/video), and Reddit posts
  now embed. Reddit uses redditmedia.com to bypass the homeserver's blocked
  preview (Reddit serves it a bot-check 'please wait for verification' page);
  a bot-wall title filter keeps that garbage out of any caption.

New pure parsers unit-tested (videoEmbed.test.ts, 17 cases). Desktop + live web
CSP frame-src updated for instagram.com, embed.tidal.com, redditmedia.com.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/components/url-preview/UrlPreview.css.tsx

@@ -14,6 +14,13 @@ export const UrlPreview = style([
   },
 ]);
 
+// Wider, responsive card for interactive embeds (video players, tweets, posts)
+// so the player chrome / tweet content isn't cramped or clipped. Defined after
+// UrlPreview so its width wins the cascade.
+export const UrlPreviewWide = style({
+  width: 'min(34rem, 92vw)',
+});
+
 export const UrlPreviewImg = style([
   DefaultReset,
   {
@@ -209,6 +216,9 @@ export const EmbedMediaLandscape = style([
     aspectRatio: '16 / 9',
     overflow: 'hidden',
     backgroundColor: color.Surface.Container,
+    selectors: {
+      '&:fullscreen': { width: '100vw', height: '100vh', aspectRatio: 'auto' },
+    },
   },
 ]);
 
@@ -216,12 +226,15 @@ export const EmbedMediaPortrait = style([
   DefaultReset,
   {
     position: 'relative',
-    width: toRem(220),
+    width: toRem(300),
     maxWidth: '100%',
     aspectRatio: '9 / 16',
     margin: '0 auto',
     overflow: 'hidden',
     backgroundColor: color.Surface.Container,
+    selectors: {
+      '&:fullscreen': { width: '100vw', height: '100vh', aspectRatio: 'auto', margin: 0 },
+    },
   },
 ]);
 
@@ -430,6 +443,16 @@ export const BadgeAppleMusic = style({
   color: '#ffffff',
 });
 
+export const BadgeInstagram = style({
+  backgroundColor: '#e1306c',
+  color: '#ffffff',
+});
+
+export const BadgeTidal = style({
+  backgroundColor: '#000000',
+  color: '#ffffff',
+});
+
 // ---------------------------------------------------------------------------
 // Twitch LIVE badge
 // ---------------------------------------------------------------------------