Merge PR #1038: surface add-time failures as failed done entries

Adds __record_add_failure so a URL that fails before a real download starts
(unsupported/unextractable URL, SSRF-rejected, extraction error) appears in the
Completed list as a red-cross entry with retry and error-detail, instead of only
a transient toast and a server log line. Keyed by info.url like any errored
download. Includes _short_title_for_failed_url for a readable hostname title.

The frontend hunk removing the 'Click for details' hint from every error row was
dropped from this merge; that affordance (added in fd3aaea, #143) is kept.

Co-authored-by: streamer1122 <streamer1122@users.noreply.github.com>

app/tests/test_ytdl_utils.py

@@ -80,6 +80,7 @@ from ytdl import (
     _resolve_outtmpl_fields,
     _sanitize_entry_for_pickle,
     _sanitize_path_component,
+    _short_title_for_failed_url,
 )
 
 # Detect whether the real yt-dlp is loaded (as opposed to the minimal fake
@@ -808,5 +809,23 @@ class CompactPersistedEntryTests(unittest.TestCase):
         self.assertIsNone(_compact_persisted_entry({"id": "x", "title": "y"}))
 
 
+class ShortTitleForFailedUrlTests(unittest.TestCase):
+    def test_uses_hostname_for_a_normal_url(self):
+        self.assertEqual(
+            _short_title_for_failed_url("https://example.com/watch?v=1"),
+            "example.com",
+        )
+
+    def test_falls_back_to_raw_value_when_there_is_no_hostname(self):
+        # file:// URIs and bare search terms/video IDs have no netloc to extract.
+        self.assertEqual(_short_title_for_failed_url("file:///etc/passwd"), "file:///etc/passwd")
+        self.assertEqual(_short_title_for_failed_url("ytsearch:some query"), "ytsearch:some query")
+
+    def test_falls_back_to_raw_value_on_unparseable_input(self):
+        # A malformed IPv6-looking host raises ValueError in urlsplit().hostname.
+        malformed = "https://[::1/watch"
+        self.assertEqual(_short_title_for_failed_url(malformed), malformed)
+
+
 if __name__ == "__main__":
     unittest.main()