feat(vision): il server esegue tramite worker e salva misure vere

Aggiunge POST /api/vision/execute: route l'immagine al worker di visione,
mappa le uscite del grafo sulle quote e le salva con save_measurement -
stesso verdetto, stesso gate del fuori tolleranza di ogni altra misura.
Nuova tabella vision_results (una riga per acquisizione, non per quota) e
input_method 'camera' su measurements.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014BBnuACZSCJqXrMYC3LUMU

src/backend/tests/test_vision_execute.py

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+"""A quote from a camera is a measurement like any other: same verdict, same gate."""
+import io
+
+import pytest
+from PIL import Image
+from sqlalchemy import select
+
+from src.backend.models.orm.measurement import Measurement
+from src.backend.models.orm.recipe import RecipeVersion
+from src.backend.models.orm.task import RecipeSubtask, RecipeTask
+from src.backend.models.orm.vision import VisionResult
+from src.backend.tests.conftest import auth_headers, create_test_recipe
+
+
+def an_image() -> bytes:
+    buffer = io.BytesIO()
+    Image.new("L", (64, 64), color=0).save(buffer, format="PNG")
+    return buffer.getvalue()
+
+
+async def recipe_parts(db_session, recipe_id: int):
+    """`create_test_recipe` returns only the recipe: here it is broken apart."""
+    version = (await db_session.execute(
+        select(RecipeVersion).where(
+            RecipeVersion.recipe_id == recipe_id,
+            RecipeVersion.is_current == True,  # noqa: E712
+        )
+    )).scalar_one()
+    task = (await db_session.execute(
+        select(RecipeTask).where(RecipeTask.version_id == version.id)
+    )).scalars().first()
+    subtask = (await db_session.execute(
+        select(RecipeSubtask).where(RecipeSubtask.task_id == task.id)
+    )).scalars().first()
+    return version, task, subtask
+
+
+@pytest.fixture
+def worker_says(monkeypatch):
+    """The worker does not run in tests: its response is faked here."""
+    def _install(outputs: dict, failures: list | None = None):
+        async def fake_call(image_bytes: bytes, graph: dict) -> dict:
+            return {
+                "outputs": outputs,
+                "failures": failures or [],
+                "engine_version": "a" * 40,
+                "duration_ms": 12,
+            }
+        monkeypatch.setattr(
+            "src.backend.services.vision_service._call_worker", fake_call,
+        )
+    return _install
+
+
+@pytest.mark.asyncio
+async def test_a_camera_quote_becomes_a_measurement(
+    client, db_session, measurement_tec_user, worker_says,
+):
+    recipe = await create_test_recipe(db_session, measurement_tec_user.id)
+    version, task, subtask = await recipe_parts(db_session, recipe.id)
+    task.task_type = "camera_measure"
+    task.vision_json = {"schema_version": 1, "name": "p", "tools": []}
+    subtask.vision_output = "t1.diameter"
+    # The fixture creates the quote with nominal 10 and tight limits around it.
+    await db_session.commit()
+    worker_says({"t1.diameter": float(subtask.nominal)})
+
+    response = await client.post(
+        "/api/vision/execute",
+        headers=auth_headers(measurement_tec_user),
+        files={"image": ("p.png", an_image(), "image/png")},
+        data={"task_id": str(task.id), "lot_number": "L1"},
+    )
+
+    assert response.status_code == 200
+    saved = (await db_session.execute(
+        select(Measurement).where(Measurement.subtask_id == subtask.id)
+    )).scalars().all()
+    assert len(saved) == 1
+    assert saved[0].pass_fail == "pass"
+    assert saved[0].input_method == "camera"
+    assert saved[0].vision_result_id is not None
+
+
+@pytest.mark.asyncio
+async def test_the_execution_records_which_engine_produced_it(
+    client, db_session, measurement_tec_user, worker_says,
+):
+    recipe = await create_test_recipe(db_session, measurement_tec_user.id)
+    version, task, subtask = await recipe_parts(db_session, recipe.id)
+    task.task_type = "camera_measure"
+    task.vision_json = {"schema_version": 1, "name": "p", "tools": []}
+    subtask.vision_output = "t1.diameter"
+    await db_session.commit()
+    worker_says({"t1.diameter": float(subtask.nominal)})
+
+    await client.post(
+        "/api/vision/execute",
+        headers=auth_headers(measurement_tec_user),
+        files={"image": ("p.png", an_image(), "image/png")},
+        data={"task_id": str(task.id), "lot_number": "L1"},
+    )
+
+    result = (await db_session.execute(select(VisionResult))).scalars().one()
+    assert result.engine_version == "a" * 40
+    assert result.executed_on == "server"
+    assert result.graph_snapshot == task.vision_json
+
+
+@pytest.mark.asyncio
+async def test_a_missing_output_names_itself(
+    client, db_session, measurement_tec_user, worker_says,
+):
+    """No half measurement: if an output is missing, the error names it."""
+    recipe = await create_test_recipe(db_session, measurement_tec_user.id)
+    version, task, subtask = await recipe_parts(db_session, recipe.id)
+    task.task_type = "camera_measure"
+    task.vision_json = {"schema_version": 1, "name": "p", "tools": []}
+    subtask.vision_output = "t1.diameter"
+    await db_session.commit()
+    worker_says({"t1.radius": 5.0})
+
+    response = await client.post(
+        "/api/vision/execute",
+        headers=auth_headers(measurement_tec_user),
+        files={"image": ("p.png", an_image(), "image/png")},
+        data={"task_id": str(task.id), "lot_number": "L1"},
+    )
+
+    assert response.status_code == 422
+    assert "t1.diameter" in response.json()["detail"]
+    assert (await db_session.execute(select(Measurement))).scalars().all() == []
+
+
+@pytest.mark.asyncio
+async def test_a_task_without_a_graph_is_refused(
+    client, db_session, measurement_tec_user, worker_says,
+):
+    recipe = await create_test_recipe(db_session, measurement_tec_user.id)
+    version, task, subtask = await recipe_parts(db_session, recipe.id)
+    task.task_type = "camera_measure"
+    await db_session.commit()
+    worker_says({})
+
+    response = await client.post(
+        "/api/vision/execute",
+        headers=auth_headers(measurement_tec_user),
+        files={"image": ("p.png", an_image(), "image/png")},
+        data={"task_id": str(task.id)},
+    )
+
+    assert response.status_code == 422
+    assert "graph" in response.json()["detail"].lower()