fc3h(tests): drop pinned migration-backup tests (retired surface; coverage moved to test_backup_service.py + test_api_system_backup.py)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/test_api_migrate.py

@@ -31,17 +31,10 @@ async def client(app):
         yield c
 
 
-@pytest.mark.asyncio
-async def test_post_backup_returns_202_and_id(client, monkeypatch):
-    monkeypatch.setattr(
-        "backend.app.api.migrate.run_migration",
-        type("F", (), {"delay": lambda self, *a, **k: None})(),
-    )
-    resp = await client.post("/api/migrate/backup", json={})
-    assert resp.status_code == 202
-    body = await resp.get_json()
-    assert "run_id" in body
-    assert body["status"] == "pending"
+# Retired 2026-05-24 (FC-3h): `test_post_backup_returns_202_and_id`
+# asserted the /api/migrate/backup endpoint, which was retired in FC-3h.
+# Backup is now a first-class feature at /api/system/backup/*;
+# coverage lives in tests/test_api_system_backup.py.
 
 
 @pytest.mark.asyncio
@@ -62,10 +55,6 @@ async def test_post_ingest_rejects_missing_file(client):
 
 @pytest.mark.asyncio
 async def test_post_ingest_accepts_multipart_file(client, monkeypatch):
-    monkeypatch.setattr(
-        "backend.app.api.migrate._has_recent_pre_migration_backup",
-        lambda: True,  # pretend backup exists
-    )
     monkeypatch.setattr(
         "backend.app.api.migrate.run_migration",
         type("F", (), {"delay": lambda self, *a, **k: None})(),
@@ -92,10 +81,9 @@ async def test_post_ingest_accepts_multipart_file(client, monkeypatch):
 
 @pytest.mark.asyncio
 async def test_post_dry_run_allowed_without_backup(client, monkeypatch):
-    monkeypatch.setattr(
-        "backend.app.api.migrate._has_recent_pre_migration_backup",
-        lambda: False,
-    )
+    # FC-3h: the _has_recent_pre_migration_backup gate was retired; dry-run
+    # ingests were always allowed and now non-dry-run ingests are too.
+    # This test stays as regression coverage that dry_run ingest still works.
     monkeypatch.setattr(
         "backend.app.api.migrate.run_migration",
         type("F", (), {"delay": lambda self, *a, **k: None})(),