fix(scheduler): drop cross-task mutex, quiet window + retry

Incident: evening full snapshot could be recorded as ok with
already_completed/elapsed=0 after mutual skip with hourly sync, then
next_run jumped to the next day.

- Full-site snapshot never skips because another task is running
- 23:00-01:00 Asia/Shanghai: defer discovery / snapshot_recent /
  candidate_cleanup to after 01:00; fans never defers
- Skip records ok=false + skipped=true (not success / not completed)
- Skip/fail reschedule soon (~5m); daily success still next snapshot_at
- TaskControl return value drives next_run; system UI shows skip fields

reaction_board/web/queries.py

@@ -34,7 +34,14 @@ from ..analytics import (
 )
 from ..config import ConfigStore
 from ..database import Database
-from ..timeutil import day_bounds, next_daily_run, shanghai_date, shanghai_datetime
+from ..timeutil import (
+    day_bounds,
+    interval_next_run,
+    next_after_snapshot_quiet_window,
+    next_daily_run,
+    shanghai_date,
+    shanghai_datetime,
+)
 from .cache import DASHBOARD_CACHE, TTL_FANS, TTL_VIDEOS, build_cache_key
 
 TRACKED_STATUSES = ("active", "unfaved")
@@ -1971,9 +1978,10 @@ class DashboardQueries:
                 "fans": int(next_daily_run(now, cfg.schedule.snapshot_at)),
                 "snapshot": int(next_daily_run(now, cfg.schedule.snapshot_at)),
                 "snapshot_seed": int(next_daily_run(now, cfg.schedule.seed_at)),
-                "discover": int(now + discover_interval),
-                "snapshot_recent": int(now + recent_interval),
+                "discover": int(interval_next_run(now, float(discover_interval))),
+                "snapshot_recent": int(interval_next_run(now, float(recent_interval))),
             }
+            retry_seconds = 300
             for name, key, at in (
                 ("fans", "fans", cfg.schedule.snapshot_at),
                 ("snapshot", "snapshot", cfg.schedule.snapshot_at),
@@ -1985,19 +1993,41 @@ class DashboardQueries:
                 if not (isinstance(record, dict) and record.get("finished_at")):
                     continue
                 finished_at = int(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 name in {"discover", "snapshot_recent"}:
-                    # 只按上次完成推下一档；进行中由 running 展示，不按墙钟抢跑。
+                    # 上次完成推下一档；skip/失败短补跑；静默窗推到 01:00 后。
                     interval = (
                         recent_interval if name == "snapshot_recent"
                         else discover_interval
                     )
-                    next_runs[name] = finished_at + interval
+                    if skipped:
+                        next_runs[name] = int(
+                            next_after_snapshot_quiet_window(float(finished_at))
+                        )
+                    elif failed:
+                        next_runs[name] = int(finished_at + retry_seconds)
+                    else:
+                        next_runs[name] = int(
+                            interval_next_run(float(finished_at), float(interval))
+                        )
                 else:
-                    next_runs[name] = int(next_daily_run(finished_at, at))
+                    if skipped or failed:
+                        # 日更任务失败/skip：短间隔补跑，绝不按成功推到次日。
+                        next_runs[name] = int(finished_at + retry_seconds)
+                    else:
+                        next_runs[name] = int(next_daily_run(finished_at, at))
             errors = [
                 {"task": name, **record}
                 for name, record in tasks.items()
-                if isinstance(record, dict) and record.get("ok") is False
+                if isinstance(record, dict)
+                and record.get("ok") is False
+                and not record.get("skipped")
+                and not (
+                    isinstance(record.get("summary"), dict)
+                    and record["summary"].get("skipped")
+                )
             ]
             counts = {str(row["status"]): int(row["n"]) for row in conn.execute(
                 "SELECT status, COUNT(*) AS n FROM video GROUP BY status"