fix(react): address Doctor findings (#1143)

Accessibility/semantics pass aligned with React Doctor: role-based spans/divs become real buttons, role=status becomes <output>, modals use native <dialog>, author/peer flags render as <img>, and embed/challenge iframes are sandboxed. Includes review follow-ups: correct button chrome/centering/themed dialog colors and focus rings, the missing aria-label i18n keys (all languages), the Yandex image-search URL, clearer .bso setup steps, a keyboard-accessible image-search dropdown, and removal of the post-edit ('comment edited') display (mod edits unchanged).

src/components/embed/embed-utils.ts

@@ -0,0 +1,60 @@
+export const youtubeHosts = new Set<string>([
+  'youtube.com',
+  'www.youtube.com',
+  'youtu.be',
+  'www.youtu.be',
+  'm.youtube.com',
+  'music.youtube.com',
+  // working Invidious instances - https://docs.invidious.io/instances/ - https://uptime.invidious.io/
+  'yewtu.be',
+  'inv.nadeko.net',
+  'yt.artemislena.eu',
+  'invidious.nerdvpn.de',
+]);
+
+export const xHosts = new Set<string>(['twitter.com', 'www.twitter.com', 'x.com', 'www.x.com']);
+
+export const getXTweetId = (parsedUrl: URL): string | undefined => {
+  const pathParts = parsedUrl.pathname.split('/').filter(Boolean);
+  const statusIndex = pathParts.findIndex((part) => part === 'status' || part === 'statuses');
+  const statusId = statusIndex === -1 ? undefined : pathParts[statusIndex + 1];
+
+  return statusId && /^\d+$/.test(statusId) ? statusId : undefined;
+};
+
+export const redditHosts = new Set<string>(['reddit.com', 'www.reddit.com', 'old.reddit.com']);
+export const twitchHosts = new Set<string>(['twitch.tv', 'www.twitch.tv']);
+export const tiktokHosts = new Set<string>(['tiktok.com', 'www.tiktok.com']);
+export const instagramHosts = new Set<string>(['instagram.com', 'www.instagram.com']);
+export const odyseeHosts = new Set<string>(['odysee.com', 'www.odysee.com']);
+export const bitchuteHosts = new Set<string>(['bitchute.com', 'www.bitchute.com']);
+export const streamableHosts = new Set<string>(['streamable.com', 'www.streamable.com']);
+export const spotifyHosts = new Set<string>(['spotify.com', 'www.spotify.com', 'open.spotify.com']);
+export const soundcloudHosts = new Set<string>(['soundcloud.com', 'www.soundcloud.com', 'on.soundcloud.com', 'api.soundcloud.com', 'w.soundcloud.com']);
+
+const canEmbedHosts = new Set<string>([
+  ...youtubeHosts,
+  ...xHosts,
+  ...redditHosts,
+  ...twitchHosts,
+  ...tiktokHosts,
+  ...instagramHosts,
+  ...odyseeHosts,
+  ...bitchuteHosts,
+  ...soundcloudHosts,
+  ...streamableHosts,
+  ...spotifyHosts,
+]);
+
+export const canEmbed = (parsedUrl: URL): boolean => {
+  if (xHosts.has(parsedUrl.host)) {
+    return Boolean(getXTweetId(parsedUrl));
+  }
+
+  if (redditHosts.has(parsedUrl.host)) {
+    // Reddit posts are not embeddable if the URL does not include '/comments/'
+    return parsedUrl.pathname.includes('/comments/');
+  }
+
+  return canEmbedHosts.has(parsedUrl.host) || (parsedUrl.host.startsWith('yt.') && parsedUrl.searchParams.has('v'));
+};