handle watchdog's file created event using the on_modified

handler

+ move processing thumbnails and album colors to the populate class
+ move processing artist colors behind the populate call in run_periodic_checks

app/lib/populate.py

@@ -7,6 +7,7 @@ from app.db.sqlite.tracks import SQLiteTrackMethods
 from app.db.sqlite.settings import SettingsSQLMethods as sdb
 from app.db.sqlite.favorite import SQLiteFavoriteMethods as favdb
 from app.db.store import Store
+from app.lib.colorlib import ProcessAlbumColors
 
 from app.lib.taglib import extract_thumb, get_tags
 from app.logger import log
@@ -65,6 +66,9 @@ class Populate:
 
         self.tag_untagged(untagged, key)
 
+        ProcessTrackThumbnails()
+        ProcessAlbumColors()
+
     @staticmethod
     def filter_untagged(tracks: list[Track], files: list[str]):
         tagged_files = [t.filepath for t in tracks]