prevent running migrations if is_fresh_install

+ fix: sqlite3.ProgrammingError: Cannot operate on a closed cursor on ProcessAlbumColors()
+ move processing artist images from periodic_scans to Populate
+ bump hash string limit from 7 to 10
+ add last_mod property to database
+ fix: TypeError: '<' not supported between instances of 'int' and 'str' on album page

app/models/track.py

@@ -19,12 +19,13 @@ class Track:
     artist: str | list[ArtistMinimal]
     bitrate: int
     copyright: str
-    date: str
+    date: int
     disc: int
     duration: int
     filepath: str
     folder: str
     genre: str | list[str]
+    last_mod: float
     title: str
     track: int
     trackhash: str