fix(scheduler): do not force full snapshot on post-seed restart

Schedule snapshot_seed/snapshot/fans to the next wall-clock seed_at /
snapshot_at on process start (optionally from last task record), instead
of next_run=0. Force-seal of seed shells only after today's snapshot_at
(or CLI --force), so a daytime restart cannot scrape the whole site.

reaction_board/cli.py

@@ -48,6 +48,7 @@ from .timeutil import (
     next_daily_run,
     parse_hhmm,
     shanghai_date,
+    shanghai_datetime,
 )
 
 ROOT = Path(__file__).resolve().parent.parent
@@ -297,6 +298,53 @@ def _defer_snapshot_seed(
     )
 
 
+def _initial_daily_next_run(
+    repo: Repository,
+    name: str,
+    at: str,
+    *,
+    now: float | None = None,
+    retry_seconds: float | None = None,
+) -> float:
+    """进程启动时日更任务的下次运行：墙钟下一档，或与系统页一致的上次记录推导。
+
+    不得返回 ``0`` / 过去时间来“立刻跑一遍”——午夜 seed 后重启否则会白天全量强采。
+    """
+    current = time.time() if now is None else float(now)
+    wall = next_daily_run(current, at)
+    raw = repo.kv_get(f"task:last:{name}")
+    if not raw:
+        return wall
+    try:
+        record = json.loads(raw)
+    except (TypeError, ValueError, json.JSONDecodeError):
+        return wall
+    if not isinstance(record, dict) or record.get("finished_at") is None:
+        return wall
+    finished_at = float(record["finished_at"])
+    summary = record.get("summary") if isinstance(record.get("summary"), dict) else {}
+    skipped = bool(record.get("skipped") or summary.get("skipped"))
+    failed = record.get("ok") is False
+    if skipped or failed:
+        gap = (
+            _SEED_RETRY_SECONDS if name == "snapshot_seed"
+            else float(_TASK_RETRY_SECONDS if retry_seconds is None else retry_seconds)
+        )
+        retry_at = finished_at + gap
+        return retry_at if retry_at > current else wall
+    scheduled = next_daily_run(finished_at, at)
+    # 成功记录推到的下一档若已过，退回墙钟下一档（严格 > now）
+    return scheduled if scheduled > current else wall
+
+
+def _reached_daily_slot(at: str, now: float | None = None) -> bool:
+    """当前上海时间是否已到达（含）今日 ``at`` 墙钟点。"""
+    current = shanghai_datetime(now)
+    hour, minute = parse_hhmm(at)
+    slot = current.replace(hour=hour, minute=minute, second=0, microsecond=0)
+    return current >= slot
+
+
 def _client(credentials, logger: JsonLogger, *, pacer=None, retries: int = 3) -> BilibiliClient:
     return BilibiliClient(
         cookie=credentials.cookie,
@@ -769,11 +817,13 @@ def cmd_run(args, logger: JsonLogger, *, serve_web: bool = False) -> int:
             started = int(time.time())
             _mark_task_running(repo, "snapshot", started_at=started)
             try:
-                # 晚间全量：若当日是午夜 seed 壳，必须 force 打穿 ok=1 克隆行。
+                # 仅晚间 snapshot_at 及之后：seed 壳才 force 打穿 ok=1 克隆行。
+                # 白天/重启不得因 seeded 标记立刻全量强采。
                 today = shanghai_date()
-                force_seed = repo.kv_get(
-                    SnapshotService.seeded_key(today)
-                ) == "1"
+                force_seed = (
+                    repo.kv_get(SnapshotService.seeded_key(today)) == "1"
+                    and _reached_daily_slot(snapshot_at, float(started))
+                )
                 summary = snapshot_service.run_if_needed(force=force_seed)
             except Exception as exc:  # noqa: BLE001
                 finished = int(time.time())
@@ -842,9 +892,10 @@ def cmd_run(args, logger: JsonLogger, *, serve_web: bool = False) -> int:
             _mark_task_running(repo, "fans", started_at=started)
             try:
                 today = shanghai_date()
-                force_seed = repo.kv_get(
-                    SnapshotService.fans_seeded_key(today)
-                ) == "1"
+                force_seed = (
+                    repo.kv_get(SnapshotService.fans_seeded_key(today)) == "1"
+                    and _reached_daily_slot(snapshot_at, float(started))
+                )
                 summary = snapshot_service.run_fans_if_needed(force=force_seed)
             except Exception as exc:  # noqa: BLE001
                 finished = int(time.time())
@@ -927,25 +978,39 @@ def cmd_run(args, logger: JsonLogger, *, serve_web: bool = False) -> int:
                 logger.info("config.reloaded", revision=store.revision)
             return {"revision": store.revision}
 
+        # --once：保持 next_run=0 立刻跑到期逻辑；常驻：日更对齐墙钟，避免重启即强采。
+        now_ts = time.time()
+        if args.once:
+            seed_next = snapshot_next = fans_next = 0.0
+        else:
+            seed_next = _initial_daily_next_run(
+                repo, "snapshot_seed", seed_at, now=now_ts,
+            )
+            snapshot_next = _initial_daily_next_run(
+                repo, "snapshot", snapshot_at, now=now_ts,
+            )
+            fans_next = _initial_daily_next_run(
+                repo, "fans", snapshot_at, now=now_ts,
+            )
         scheduler = Scheduler(
             [
                 ScheduledTask(
                     "snapshot_seed",
                     86400.0,
                     run_snapshot_seed,
-                    next_run=0.0,
+                    next_run=seed_next,
                 ),
                 ScheduledTask(
                     "snapshot",
                     86400.0,
                     run_snapshot,
-                    next_run=0.0,
+                    next_run=snapshot_next,
                 ),
                 ScheduledTask(
                     "fans",
                     86400.0,
                     run_fans,
-                    next_run=0.0,
+                    next_run=fans_next,
                 ),
                 ScheduledTask(
                     "snapshot_recent",