YouTube enricher: reliable full coverage without a proxy + sweep existing follows

Two gaps from real use:
- When all proxy instances are down (common), the fallback only dated WISHED
  videos, leaving most as 'Earlier videos'. Now on proxy failure it flat-resolves
  the channel's recent uploads and dates THOSE via yt-dlp (throttled, cached) —
  so years populate fully even with no working proxy.
- A channel followed before the enricher existed was never queued ('nothing to
  process'). /youtube/channels now sweeps: any followed channel not enriched
  recently gets enqueued — so viewing the Channels tab (or the wishlist badge
  refresh) picks up existing follows.

The detail page still reads cache+RSS (fast); the enricher fills the cache. 51
tests green.

api/video/youtube.py

@@ -111,11 +111,22 @@ def register_routes(bp):
 
     @bp.route("/youtube/channels", methods=["GET"])
     def video_youtube_channels():
-        """Followed channels (newest first) for the watchlist page."""
+        """Followed channels (newest first) for the watchlist page. Also sweeps:
+        any followed channel not date-enriched recently gets queued for the
+        background enricher (so existing follows get picked up, not just new ones)."""
         from . import get_video_db
         try:
             db = get_video_db()
-            return jsonify({"success": True, "channels": db.list_watchlist_channels(),
+            channels = db.list_watchlist_channels()
+            try:
+                from core.video.youtube_enrichment import get_youtube_date_enricher
+                enr = get_youtube_date_enricher()
+                for c in channels:
+                    if not db.channel_dates_enriched_recently(c["youtube_id"]):
+                        enr.enqueue(c["youtube_id"], c.get("title"))
+            except Exception:
+                pass
+            return jsonify({"success": True, "channels": channels,
                             "counts": db.youtube_wishlist_counts()})
         except Exception:
             logger.exception("youtube channels list failed")

core/video/youtube_enrichment.py

@@ -121,8 +121,18 @@ class YoutubeDateEnricher:
             db.cache_video_dates([{"youtube_id": k, "published_at": v} for k, v in dates.items()])
             logger.info("YouTube dates: %d cached for %s (proxy)", len(dates), cid)
 
-        # Fallback: per-video for the channel's wished videos still lacking a date.
-        ids = db.wishlisted_video_ids_for_channel(cid)
+        # Fallback (proxy down): date the channel's RECENT UPLOADS via yt-dlp, not
+        # just wished videos — so years populate fully even with no working proxy.
+        ids = set(db.wishlisted_video_ids_for_channel(cid))
+        if not dates:
+            try:
+                ch = yt.resolve_channel("https://www.youtube.com/channel/" + cid, limit=60)
+                for v in (ch or {}).get("videos") or []:
+                    if v.get("youtube_id"):
+                        ids.add(v["youtube_id"])
+            except Exception:
+                logger.info("flat resolve for date fallback failed for %s", cid, exc_info=True)
+        ids = list(ids)
         have = db.get_video_dates(ids)
         missing = [i for i in ids if i not in have and i not in dates]
         filled = 0

tests/test_video_youtube_enrichment.py

@@ -33,8 +33,11 @@ def test_enrich_caches_proxy_dates_and_marks_done(db, monkeypatch):
 def test_enrich_falls_back_to_per_video_when_proxy_empty(db, monkeypatch):
     import core.video.youtube as yt
     monkeypatch.setattr(yt, "proxy_channel_dates", lambda cid, *a, **k: {})   # all proxies down
+    # flat resolve adds a recent upload r1 to the date-fallback set (besides wished w1/w2)
+    monkeypatch.setattr(yt, "resolve_channel",
+                        lambda url, **k: {"videos": [{"youtube_id": "r1", "title": "Recent"}]})
     monkeypatch.setattr(yt, "video_detail",
-                        lambda vid: {"youtube_id": vid, "published_at": "2022-03-03"} if vid == "w1" else None)
+                        lambda vid: {"youtube_id": vid, "published_at": "2022-03-03"} if vid in ("w1", "r1") else None)
     import core.video.youtube_enrichment as mod
     monkeypatch.setattr(mod.time, "sleep", lambda s: None)   # no real throttle delay in tests
     db.add_videos_to_wishlist({"youtube_id": "UCx", "title": "X"},
@@ -42,7 +45,8 @@ def test_enrich_falls_back_to_per_video_when_proxy_empty(db, monkeypatch):
 
     e = YoutubeDateEnricher(db_factory=lambda: db)
     e._enrich("UCx")
-    assert db.get_video_dates(["w1", "w2"]) == {"w1": "2022-03-03"}   # only w1 had a date
+    # w1 (wished) + r1 (recent upload from flat resolve) got dates; w2 had none
+    assert db.get_video_dates(["w1", "w2", "r1"]) == {"w1": "2022-03-03", "r1": "2022-03-03"}
     assert db.channel_dates_enriched_recently("UCx") is True