fix(alembic-migration)

backend/migrations/versions/0002_add_push_subscriptions.py

@@ -7,6 +7,7 @@ Create Date: 2025-01-27
 """
 from alembic import op
 import sqlalchemy as sa
+from sqlalchemy import inspect
 
 
 # revision identifiers, used by Alembic.
@@ -17,6 +18,12 @@ depends_on = None
 
 
 def upgrade():
+    # Check if table already exists (idempotent migration)
+    conn = op.get_bind()
+    inspector = inspect(conn)
+    tables = inspector.get_table_names()
+    
+    if 'push_subscriptions' not in tables:
         op.create_table(
             'push_subscriptions',
             sa.Column('id', sa.Integer(), nullable=False),