Artist-detail: keep the library view when a source id is ambiguous

After the duplicate-id ambiguity guard, an owned artist reached via a source
link (e.g. Kendrick's Deezer link) fell back to the bare source-only view
instead of the rich library view, because the URL path carries no name and the
duplicated id alone can't be matched.

get_artist_detail now resolves the source artist's name (reusing the #775
link-resolver's per-source artist fetch) when the id lookup is ambiguous and no
name was passed, then retries the library upgrade by name. So an owned artist
lands on the full library view; a genuinely-unowned one still renders
source-only (now with its name pre-resolved). Unique ids are unaffected.

web_server.py

@@ -7653,6 +7653,26 @@ def _find_library_artist_for_source(database, source, source_artist_id, artist_n
     )
 
 
+def _resolve_source_artist_name(source, artist_id):
+    """Resolve a source artist's display name by id, or '' on any failure.
+
+    Reuses the #775 link-resolver's per-source artist fetch so we have one
+    place that knows each source's get-by-id quirks. Used by the artist-detail
+    library upgrade to disambiguate a duplicated/corrupt source id by name
+    when the URL-driven navigation didn't carry a name.
+    """
+    try:
+        deps = _build_search_deps()
+        client, _available = _search_orchestrator.resolve_client(source, deps)
+        if client is None:
+            return ''
+        data = _search_by_id._fetch_artist(client, source, artist_id)
+        return (data or {}).get('name') or ''
+    except Exception as e:
+        logger.debug(f"Source artist name resolution failed for {source}:{artist_id}: {e}")
+        return ''
+
+
 def _build_source_only_artist_detail(artist_id, artist_name, source):
     """Thin wrapper around ``core.artist_source_detail.build_source_only_artist_detail``.
 
@@ -7754,6 +7774,18 @@ def get_artist_detail(artist_id):
             library_pk = _find_library_artist_for_source(
                 database, source_param, artist_id, artist_name_arg
             )
+            # URL-driven navigation carries no name, so a duplicated/corrupt
+            # source id (one Deezer id on several artists) can't be matched by
+            # the id alone — it's ambiguous and the lookup bails. Resolve the
+            # artist's name from the source and retry so an owned artist still
+            # gets the rich library view instead of the bare source one.
+            if not library_pk and not artist_name_arg:
+                resolved_name = _resolve_source_artist_name(source_param, artist_id)
+                if resolved_name:
+                    artist_name_arg = resolved_name
+                    library_pk = _find_library_artist_for_source(
+                        database, source_param, artist_id, artist_name_arg
+                    )
             if library_pk:
                 logger.info(
                     f"Source-id {source_param}:{artist_id} matched library artist "