style: drop redundant comments and apply formatting

Frontend now uses double quotes and semicolons. No behaviour change.

backend/db.py

@@ -44,7 +44,6 @@ def _connection():
 
 
 def _finish_transaction(response):
-    # Commit only successful responses so a 4xx/5xx never leaves partial writes behind.
     conn = g.get("db")
     if conn is not None:
         if response.status_code < 400:
@@ -57,5 +56,5 @@ def _finish_transaction(response):
 def _release_connection(_exc):
     conn = g.pop("db", None)
     if conn is not None:
-        conn.rollback()  # no-op after commit; discards work if after_request never ran
+        conn.rollback()
         current_app.extensions["db_pool"].putconn(conn)