refactor: extract admin business logic to services, introduce job queue, add derived index helpers

- Move DB operations from routes/admin.py to services/admin.py (get_logs_context, query_summary_statuses, retry_failed, delete/reset operations)
- Add services/jobs.py with Job/JobEvent-based async job queue (create_job, run_job, enqueue_job)
- Add services/derived.py with FTS5 reindex and paper index deletion helpers
- Refactor scheduler to use job queue instead of direct pipeline calls
- Add heartbeat_at/expires_at to TaskLock for lock health tracking
- Remove DESIGN_REVIEW.md
- Update tests: remove redundant integration tests, add unit tests for new services

tests/test_crawler.py

@@ -10,6 +10,7 @@ from app.services.crawler import (
     _parse_paper,
     crawl_daily,
     fetch_daily,
+    refresh_upvotes,
     upsert_papers,
 )
 
@@ -187,3 +188,62 @@ class TestCrawlDaily:
 
         assert result["status"] == "failed"
         assert "network error" in result["error"]
+
+
+class TestRefreshUpvotes:
+    @pytest.mark.asyncio
+    async def test_refresh_updates_existing_without_inserting_new(
+        self, db_session, sample_paper
+    ):
+        sample_paper.arxiv_id = "1706.03762"
+        sample_paper.upvotes = 10
+        db_session.commit()
+
+        with patch(
+            "app.services.crawler.fetch_daily",
+            new_callable=AsyncMock,
+            return_value=[
+                {
+                    "paper": {
+                        "id": "1706.03762",
+                        "upvotes": 999,
+                        "authors": [],
+                        "tags": [],
+                    }
+                },
+                {
+                    "paper": {
+                        "id": "2010.11929",
+                        "upvotes": 123,
+                        "authors": [],
+                        "tags": [],
+                    }
+                },
+            ],
+        ):
+            result = await refresh_upvotes(db_session, days=1)
+
+        db_session.refresh(sample_paper)
+        assert result["status"] == "success"
+        assert result["updated"] == 1
+        assert sample_paper.upvotes == 999
+        assert db_session.query(type(sample_paper)).count() == 1
+
+    @pytest.mark.asyncio
+    async def test_refresh_returns_partial_when_one_day_fails(self, db_session):
+        async def _fetch_daily(target_date):
+            if target_date.endswith("01"):
+                raise ConnectionError("hf down")
+            return []
+
+        with (
+            patch(
+                "app.services.crawler.recent_date_strs",
+                return_value=["2024-01-01", "2024-01-02"],
+            ),
+            patch("app.services.crawler.fetch_daily", side_effect=_fetch_daily),
+        ):
+            result = await refresh_upvotes(db_session, days=2)
+
+        assert result["status"] == "partial"
+        assert result["errors"] == ["2024-01-01: hf down"]