feat(backend): CRUD variétés, plantations, tâches + tests

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/tests/test_varieties.py

@@ -0,0 +1,26 @@
+def test_create_variety(client):
+    r = client.post("/api/varieties", json={"nom_commun": "Tomate", "famille": "Solanacées"})
+    assert r.status_code == 201
+    assert r.json()["nom_commun"] == "Tomate"
+
+
+def test_list_varieties(client):
+    client.post("/api/varieties", json={"nom_commun": "Tomate"})
+    client.post("/api/varieties", json={"nom_commun": "Courgette"})
+    r = client.get("/api/varieties")
+    assert r.status_code == 200
+    assert len(r.json()) == 2
+
+
+def test_get_variety(client):
+    r = client.post("/api/varieties", json={"nom_commun": "Basilic"})
+    id = r.json()["id"]
+    r2 = client.get(f"/api/varieties/{id}")
+    assert r2.status_code == 200
+
+
+def test_delete_variety(client):
+    r = client.post("/api/varieties", json={"nom_commun": "Test"})
+    id = r.json()["id"]
+    r2 = client.delete(f"/api/varieties/{id}")
+    assert r2.status_code == 204