feat: implement billing system with Pally integration

- Added billing models and repository for handling bills.
- Introduced BillingService to manage payment initiation and bill creation.
- Updated user service to remove ticket-related functionality.
- Refactored settings to include new billing-related fields.
- Removed ticket-related handlers and schemas.
- Added new billing handlers for processing payments.
- Updated database schema with new bills table and status enum.
- Enhanced utility functions to calculate prices considering discounts.
- Introduced prehandling for non-private messages.
- Updated main application to initialize new billing services and repositories.

alembic/versions/d21c5f9364ea_billing.py

@@ -0,0 +1,41 @@
+"""billing
+
+Revision ID: d21c5f9364ea
+Revises: f40cab941564
+Create Date: 2026-04-23 19:22:45.686671
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = 'd21c5f9364ea'
+down_revision: Union[str, Sequence[str], None] = 'f40cab941564'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Upgrade schema."""
+    # 1. Сначала создаем тип в базе данных
+    # Имя 'billstatus' должно совпадать с тем, что в ошибке
+    bind = op.get_bind()
+    if bind.dialect.name == 'postgresql':
+        op.execute("CREATE TYPE billstatus AS ENUM ('NEW', 'PROCESS', 'UNDERPAID', 'SUCCESS', 'OVERPAID', 'FAIL')")
+
+    # 2. Теперь добавляем колонку, которая использует этот тип
+    op.add_column('bills', sa.Column('status', sa.Enum('NEW', 'PROCESS', 'UNDERPAID', 'SUCCESS', 'OVERPAID', 'FAIL', name='billstatus'), nullable=False))
+
+
+def downgrade() -> None:
+    """Downgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_column('bills', 'status')
+
+    bind = op.get_bind()
+    if bind.dialect.name == 'postgresql':
+        op.execute("DROP TYPE billstatus")
+    # ### end Alembic commands ###