feat: add supported sites page, remove yt-dlp mentions from public copy

yt-dlp is an internal implementation detail and should not be exposed
on the public site. Replace direct mentions in the platforms and FAQ
sections with a link to a new /supported-sites page listing every
extractor from yt-dlp's supported-sites doc (searchable, grouped
alphabetically), translated across en/fr/es/it.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

messages/en.json

@@ -54,7 +54,7 @@
   "platforms": {
     "heading": "Supported platforms",
     "subheading": "Works with your favorite sites",
-    "more": "+ 1000 more sites supported via yt-dlp",
+    "more": "+ 1000 more sites supported. <link>See the full list</link>.",
     "disclaimer": "Ombrora is not affiliated with YouTube, TikTok, Instagram, Facebook, X, Vimeo, Twitch, SoundCloud or Dailymotion. Please respect copyright and only download content you have the right to use."
   },
   "faq": {
@@ -64,7 +64,7 @@
     "q2": "Is it legal to download videos?",
     "a2": "Downloading is legal for content you own the rights to, that is in the public domain, or that you have permission to save for personal, offline use. You are responsible for respecting the copyright and terms of service of the source platform.",
     "q3": "Which sites are supported?",
-    "a3": "YouTube, TikTok, Instagram, Facebook, X (Twitter), Vimeo, Twitch, SoundCloud, Dailymotion and over 1000 other sites, powered by yt-dlp.",
+    "a3": "YouTube, TikTok, Instagram, Facebook, X (Twitter), Vimeo, Twitch, SoundCloud, Dailymotion and over 1000 other sites. <link>See the full list</link>.",
     "q4": "What formats and quality can I get?",
     "a4": "Video in MP4, WebM or MKV, or audio-only in MP3, up to 1080p depending on the source video.",
     "q5": "Do you keep a copy of my videos?",
@@ -76,6 +76,17 @@
     "q8": "Why did my download fail?",
     "a8": "Some videos are private, age-restricted, geo-blocked or region-locked by the source platform and cannot be downloaded. Live streams in progress and unreleased premieres are not supported either."
   },
+  "supportedSitesPage": {
+    "title": "Supported sites -- Ombrora",
+    "description": "Full list of sites supported for video and audio downloads on Ombrora.",
+    "back": "← Back to home",
+    "heading": "Supported sites",
+    "subheading": "Browse or search the full list of sites Ombrora can download from.",
+    "searchPlaceholder": "Search a site...",
+    "resultCount": "{count} of {total} sites",
+    "noResults": "No site matches your search.",
+    "note": "This list is indicative and evolves over time: some entries may stop working if a source platform changes its restrictions, and new sites are added regularly. Don't see your site? Try pasting the link anyway, it may still work."
+  },
   "footer": {
     "copyright": "© 2026 Ombrora"
   }