feat(scheduler): persist task state/progress/due_at across restart (#8)

Replace process-start next_run=0 guesses with kv task:state records
(status, due_at, stat_date, progress). Startup recovers stale running,
honors future due_at for delayed retries, and resumes the same
stat_date. Seed only enqueues evening seal; seal force keeps non-seed
ok=1 as progress (keep_scraped). Keeps !7 fail-logging and cleanup retry.

tests/test_snapshot.py

@@ -661,6 +661,50 @@ def test_seeded_day_skips_without_force_and_seals_with_force():
             db.close()
 
 
+def test_seal_keep_scraped_skips_view_progress_punches_seed():
+    """晚间 seal（keep_scraped）：已 view 的 ok=1 作进度跳过，seed 壳仍打穿。"""
+    clock = 1_800_000_000
+    with tempfile.TemporaryDirectory() as tmp:
+        transport = SnapshotTransport({
+            1: view_for(1, view=111),
+            2: view_for(2, view=222),
+        })
+        db, repo, service = make_service(tmp, transport)
+        try:
+            add_video(repo, 1)
+            add_video(repo, 2)
+            today = DATE
+            # 两条 seed 壳
+            for aid, view in ((1, 10), (2, 20)):
+                repo.upsert_snapshot(
+                    today, aid,
+                    metrics={"view": view, "like": 1, "coin": 0, "favorite": 0,
+                             "share": 0, "reply": 0, "danmaku": 0},
+                    ok=True, err=None, captured_at=clock, src="seed",
+                )
+            # 模拟 seal 中途：aid=1 已真实采集
+            repo.upsert_snapshot(
+                today, 1,
+                metrics={"view": 111, "like": 1, "coin": 0, "favorite": 0,
+                         "share": 0, "reply": 0, "danmaku": 0},
+                ok=True, err=None, captured_at=clock + 1, src="view",
+            )
+            repo.kv_set(service.seeded_key(today), "1")
+
+            sealed = service.run_if_needed(date=today, force=True)
+            assert sealed.completed is True
+            assert sealed.skipped >= 1  # aid=1 进度跳过
+            assert sealed.success >= 1  # aid=2 seed 打穿
+            # 只应请求 aid=2 的 view（aid=1 已是 view 进度）
+            assert transport.count("/web-interface/view") == 1
+            assert int(repo.get_snapshot(today, 1)["view"]) == 111
+            assert repo.get_snapshot(today, 1)["src"] == "view"
+            assert int(repo.get_snapshot(today, 2)["view"]) == 222
+            assert repo.get_snapshot(today, 2)["src"] == "view"
+        finally:
+            db.close()
+
+
 def main():
     test_snapshot_success_resume_and_force()
     test_resume_skips_ok_and_retries_failed()
@@ -679,6 +723,7 @@ def main():
     test_seed_same_day_completed_is_already_completed_not_no_source()
     test_seed_from_last_completed_does_not_mark_completed()
     test_seeded_day_skips_without_force_and_seals_with_force()
+    test_seal_keep_scraped_skips_view_progress_punches_seed()
     print("OK: 每日快照、断点续跑、失败占位与粉丝采集测试全部通过")