backend: camera e modo di analisi nel task, /vision/check senza salvataggio (Refs #97)

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

src/backend/migrations/versions/021_task_acquisition.py

@@ -0,0 +1,31 @@
+"""recipe_tasks.acquisition_json (#97)
+
+recipe_tasks.acquisition_json: camera e modo di analisi scelti nel task,
+{"camera_url", "camera_source", "modo": "impulsiva" | "in_linea"}; NULL = la
+camera della stazione dell'operatore, analisi impulsiva (come prima).
+
+Revision ID: 021_task_acquisition
+Revises: 020_station_camera
+Create Date: 2026-10-24
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+revision: str = '021_task_acquisition'
+down_revision: Union[str, None] = '020_station_camera'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # batch_alter_table come nelle migrazioni vicine: serve a SQLite
+    with op.batch_alter_table('recipe_tasks') as batch:
+        batch.add_column(sa.Column('acquisition_json', sa.JSON(), nullable=True))
+
+
+def downgrade() -> None:
+    with op.batch_alter_table('recipe_tasks') as batch:
+        batch.drop_column('acquisition_json')