Initial implementation of custom price triggers

- likely to have some bugs, but this is good enough for a preview release.

token_bot/ui/action_row/tracker.py

@@ -3,11 +3,13 @@ from interactions import ActionRow
 from token_bot.ui.buttons.tracker.alert_category import (
     HIGH_ALERT_BUTTON,
     LOW_ALERT_BUTTON,
+    CUSTOM_ALERT_BUTTON,
 )
 
 ALERT_TYPE_ROW: list[ActionRow] = [
     ActionRow(
         HIGH_ALERT_BUTTON,
         LOW_ALERT_BUTTON,
+        CUSTOM_ALERT_BUTTON,
     )
 ]