refactor: remove triggered_by field from webhook triggers and use automatic sync

- Remove triggered_by field from WorkflowWebhookTrigger model
- Replace manual webhook creation/deletion APIs with automatic sync via WebhookService
- Keep only GET API for retrieving webhook information
- Use same webhook ID for both debug and production environments (differentiated by endpoint)
- Add sync_webhook_relationships to automatically manage webhook lifecycle
- Update tests to remove triggered_by references
- Clean up unused imports and fix type checking issues

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

api/migrations/versions/2025_08_23_2039-5871f634954d_add_workflow_webhook_table.py

@@ -25,12 +25,11 @@ def upgrade():
     sa.Column('node_id', sa.String(length=64), nullable=False),
     sa.Column('tenant_id', models.types.StringUUID(), nullable=False),
     sa.Column('webhook_id', sa.String(length=24), nullable=False),
-    sa.Column('triggered_by', sa.String(length=16), nullable=False),
     sa.Column('created_by', models.types.StringUUID(), nullable=False),
     sa.Column('created_at', sa.DateTime(), server_default=sa.text('CURRENT_TIMESTAMP'), nullable=False),
     sa.Column('updated_at', sa.DateTime(), server_default=sa.text('CURRENT_TIMESTAMP'), nullable=False),
     sa.PrimaryKeyConstraint('id', name='workflow_webhook_trigger_pkey'),
-    sa.UniqueConstraint('app_id', 'node_id', 'triggered_by', name='uniq_node'),
+    sa.UniqueConstraint('app_id', 'node_id', name='uniq_node'),
     sa.UniqueConstraint('webhook_id', name='uniq_webhook_id')
     )
     with op.batch_alter_table('workflow_webhook_triggers', schema=None) as batch_op: