Clarify diagnostic language and explanations

serato_doctor/health.py

@@ -52,6 +52,9 @@ def analyze_health(library: Library) -> HealthReport:
     database_path_counts = Counter(
         normalize(str(track.path)) for track in database_tracks
     )
+    missing_database_tracks = [
+        track for track in database_tracks if not track.path.exists()
+    ]
 
     return HealthReport(
         score=score,
@@ -99,9 +102,13 @@ def analyze_health(library: Library) -> HealthReport:
         database_unmatched_entries=sum(
             normalize(track.filename) not in library_names for track in database_tracks
         ),
+        database_missing_paths=len(missing_database_tracks),
+        database_missing_unique_filenames=len(
+            {normalize(track.filename) for track in missing_database_tracks}
+        ),
         tracks_missing_from_database=sum(
             normalize(track.filename) not in database_names for track in library.tracks
-        ),
+        ) if library.database else 0,
         duplicate_database_paths=sum(
             count - 1 for count in database_path_counts.values() if count > 1
         ),