feat: add subscription and transaction repositories

- Implemented SubscriptionRepository with methods to get, create, and update subscriptions.
- Added BalanceTXRepository for creating and retrieving balance transactions.
- Introduced a test script for simulating Pally webhook for local testing.

alembic/versions/b2ecec0ef260_plan_specifications_added.py

@@ -0,0 +1,36 @@
+"""plan specifications added
+
+Revision ID: b2ecec0ef260
+Revises: e8da1e4516fa
+Create Date: 2026-04-27 20:16:04.252427
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = 'b2ecec0ef260'
+down_revision: Union[str, Sequence[str], None] = 'e8da1e4516fa'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Upgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.add_column('subscriptions', sa.Column('devices', sa.INTEGER(), nullable=False, server_default="3"))
+    op.add_column('subscriptions', sa.Column('whitelists', sa.BOOLEAN(), nullable=False, server_default="false"))
+    # ### end Alembic commands ###
+    op.alter_column("subscriptions", "devices", server_default=None)
+    op.alter_column("subscriptions", "whitelists", server_default=None)
+
+
+def downgrade() -> None:
+    """Downgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_column('subscriptions', 'whitelists')
+    op.drop_column('subscriptions', 'devices')
+    # ### end Alembic commands ###