fix: default seed_at to 00:00 (HH:MM)

Keep daily tasks next_run=0 startup catch-up; only move midnight
seed schedule default from 00:01 to 00:00 across config/docs/tests.

tests/test_config.py

@@ -142,6 +142,8 @@ def test_analytics_defaults_and_validation():
         assert cfg.analytics.home_growth_days == "auto"
         assert cfg.schedule.recent_snapshot_minutes == 60
         assert cfg.schedule.recent_video_days == 2
+        assert cfg.schedule.snapshot_at == "23:15"
+        assert cfg.schedule.seed_at == "00:00"
 
         data = base_config()
         data["analytics"] = {
@@ -155,7 +157,7 @@ def test_analytics_defaults_and_validation():
         data["schedule"] = {
             "discover_minutes": 30,
             "snapshot_at": "23:15",
-            "seed_at": "00:01",
+            "seed_at": "00:00",
             "candidate_ttl_days": 7,
             "recent_snapshot_minutes": 15,
             "recent_video_days": 3,
@@ -278,7 +280,7 @@ def test_schedule_recent_validation():
             data["schedule"] = {
                 "discover_minutes": 60,
                 "snapshot_at": "23:15",
-                "seed_at": "00:01",
+                "seed_at": "00:00",
                 "candidate_ttl_days": 7,
                 **bad,
             }