feat(core+frontend): bare yt:ID resolves to YouTube video

determine_source: yt:ID / youtube:ID with no prefix and exactly 11
chars [A-Za-z0-9_-] → YouTubeVideo via is_youtube_video_id helper.
Reserved prefixes (playlist/, channel/, c/, user/, @) still fire first
so they are unaffected by the fallback.

expand_shorthand_to_url: bare yt:ID expands to watch?v=ID using the
same predicate, consistent with how ytm:ID → music.youtube.com/watch.

isVideoSource (frontend): same 11-char /^[A-Za-z0-9_-]{11}$/ regex so
yt:ID triggers the quality probe and capture-row guards identically to
yt:video/ID.

Tests: test_is_youtube_video_id covers valid IDs (alphanumeric, with _
and -), too-short, too-long, and invalid-char cases using genuinely
invalid fixtures. test_youtube_sources adds bare-ID cases and confirms
reserved prefixes (playlist/, @) are not affected.

crates/archivr-core/src/capture.rs

@@ -211,6 +211,12 @@ fn generate_entry_title(source: Source, meta: &PlatformMetadata) -> String {
         Source::Other => "Archived Content".to_string(),
     }
 }
+/// Returns true when `s` is a valid bare YouTube video ID:
+/// exactly 11 characters from the set `[A-Za-z0-9_-]`.
+fn is_youtube_video_id(s: &str) -> bool {
+    s.len() == 11 && s.bytes().all(|b| b.is_ascii_alphanumeric() || b == b'_' || b == b'-')
+}
+
 
 fn expand_shorthand_to_url(path: &str, source: &Source) -> String {
     // YouTube shorthands: yt:video/ID, yt:playlist/ID, yt:@handle, yt:channel/ID, etc.
@@ -238,6 +244,10 @@ fn expand_shorthand_to_url(path: &str, source: &Source) -> String {
             if let Some(handle) = after.strip_prefix("@") {
                 return format!("https://www.youtube.com/@{handle}");
             }
+            // bare yt:ID — validated 11-char video ID
+            if is_youtube_video_id(after) {
+                return format!("https://www.youtube.com/watch?v={after}");
+            }
         }
     }
 
@@ -328,6 +338,11 @@ fn determine_source(path: &str) -> Source {
         {
             return Source::YouTubeChannel;
         }
+
+        // bare yt:ID — exactly 11 chars [A-Za-z0-9_-], no slash/@ prefixes
+        if is_youtube_video_id(after_scheme) {
+            return Source::YouTubeVideo;
+        }
     }
 
     // Shorthand scheme: ytm:
@@ -2110,6 +2125,15 @@ mod tests {
                 url: "youtube:@CoreDumpped",
                 expected: Source::YouTubeChannel,
             },
+            // Bare video ID — exactly 11 chars [A-Za-z0-9_-]
+            TestCase { url: "yt:dQw4w9WgXcQ",    expected: Source::YouTubeVideo },
+            TestCase { url: "youtube:dQw4w9WgXcQ", expected: Source::YouTubeVideo },
+            TestCase { url: "yt:a_b-c_d-e_4",    expected: Source::YouTubeVideo },
+            // Non-ID: wrong length (9 chars) → Other
+            TestCase { url: "yt:not-video",        expected: Source::Other },
+            // Reserved prefixes still route correctly when segment looks like an ID
+            TestCase { url: "yt:playlist/dQw4w9WgXcQ", expected: Source::YouTubePlaylist },
+            TestCase { url: "yt:@dQw4w9WgXcQ",         expected: Source::YouTubeChannel },
         ];
 
         for case in &shorthand_cases {
@@ -2122,6 +2146,18 @@ mod tests {
         }
     }
 
+    #[test]
+    fn test_is_youtube_video_id() {
+        assert!(is_youtube_video_id("dQw4w9WgXcQ"), "canonical ID");
+        assert!(is_youtube_video_id("a_b-c_d-e_4"), "11-char ID with _ and -");
+        assert!(!is_youtube_video_id(""), "empty");
+        assert!(!is_youtube_video_id("short"),       "too short");
+        assert!(!is_youtube_video_id("toolong12345"),  "too long (12 chars)");
+        assert!(!is_youtube_video_id("dQw4w9WgXc!"),   "invalid char (! at pos 11)");
+        assert!(!is_youtube_video_id("not-video"),     "9 chars — too short");
+        assert!(!is_youtube_video_id("dQw4w9WgXC!!"),  "12 chars + bad char");
+    }
+
     #[test]
     fn test_youtube_music_sources() {
         // --- determine_source ---

crates/archivr-server/static/index.html

@@ -4,7 +4,7 @@
     <meta charset="utf-8" />
     <meta name="viewport" content="width=device-width, initial-scale=1" />
     <title>Archivr</title>
-    <script type="module" crossorigin src="/assets/index-DMYakNuy.js"></script>
+    <script type="module" crossorigin src="/assets/index-BlDAGZHO.js"></script>
     <link rel="stylesheet" crossorigin href="/assets/index-D8ic-z4p.css">
   </head>
   <body>

frontend/src/components/CaptureDialog.jsx

@@ -14,7 +14,11 @@ function isVideoSource(locator) {
   for (const scheme of ['yt:', 'youtube:']) {
     if (ll.startsWith(scheme)) {
       const after = ll.slice(scheme.length)
-      return after.startsWith('video/') || after.startsWith('short/') || after.startsWith('shorts/')
+      if (after.startsWith('video/') || after.startsWith('short/') || after.startsWith('shorts/'))
+        return true
+      // bare yt:ID — exactly 11 chars [A-Za-z0-9_-], same predicate as is_youtube_video_id in core
+      if (/^[a-z0-9_-]{11}$/i.test(after)) return true
+      return false
     }
   }