fix(sync): strip blank lines from channel descriptions before storing

YouTube channel descriptions pad their contact/link blocks with runs of blank
lines, which the About popover renders verbatim (whitespace-pre-wrap) — wasted
space and storage, and noise in the search_vector. Add normalize_description()
and apply it at both channel store sites (full details + initial import) so the
DB holds the clean text. New channels are clean immediately; existing rows heal
on their next metadata re-sync. Unit-tested in test_utils.

backend/app/sync/subscriptions.py

@@ -6,6 +6,7 @@ from sqlalchemy import select
 from sqlalchemy.orm import Session
 
 from app.models import Channel, Subscription, User
+from app.utils import normalize_description
 from app.youtube.client import YouTubeClient, best_thumbnail
 
 log = logging.getLogger("siftlode.sync")
@@ -55,7 +56,7 @@ def apply_channel_details(db: Session, items: list[dict]) -> None:
 
         channel.title = snippet.get("title") or channel.title
         channel.handle = snippet.get("customUrl")
-        channel.description = snippet.get("description")
+        channel.description = normalize_description(snippet.get("description"))
         channel.thumbnail_url = (
             best_thumbnail(snippet.get("thumbnails")) or channel.thumbnail_url
         )
@@ -104,7 +105,7 @@ def import_subscriptions(db: Session, user: User) -> dict:
                 channel = Channel(
                     id=cid,
                     title=sub.get("title"),
-                    description=sub.get("description"),
+                    description=normalize_description(sub.get("description")),
                     thumbnail_url=sub.get("thumbnail_url"),
                 )
                 db.add(channel)

backend/app/utils.py

@@ -36,3 +36,15 @@ def to_tsquery_str(q: str) -> str | None:
         return None
     tokens[-1] = tokens[-1] + ":*"
     return " & ".join(tokens)
+
+
+def normalize_description(text: str | None) -> str | None:
+    """Strip whitespace-only lines from a channel/video description before storing. YouTube
+    descriptions pad contact/link blocks with runs of blank lines; keeping them wastes storage,
+    bloats the About popover, and adds nothing to the search document. Drops purely-empty lines and
+    right-strips each kept line. None stays None; all-blank collapses to "". Applied at the
+    sync/store site so the DB (and the derived search_vector) holds the clean text."""
+    if text is None:
+        return None
+    kept = [line.rstrip() for line in text.splitlines() if line.strip()]
+    return "\n".join(kept)

backend/tests/test_utils.py

@@ -1,7 +1,7 @@
 """iso(): the single date/datetime→JSON serializer the routes share (R6 S1a)."""
 from datetime import date, datetime, timezone
 
-from app.utils import iso
+from app.utils import iso, normalize_description
 
 
 def test_none_maps_to_none():
@@ -28,3 +28,25 @@ def test_matches_datetime_isoformat_contract():
     # hand-roll `x.isoformat() if x else None`.
     dt = datetime(2020, 1, 2, 3, 4, 5, 678901, tzinfo=timezone.utc)
     assert iso(dt) == dt.isoformat()
+
+
+def test_normalize_description_none_stays_none():
+    assert normalize_description(None) is None
+
+
+def test_normalize_description_drops_blank_lines():
+    # A YouTube contact block padded with runs of blank lines — the waste we strip before storing.
+    raw = "Contact us\n\n\nEmail: a@b.com\n \nInstagram: @x\n\n\n"
+    assert normalize_description(raw) == "Contact us\nEmail: a@b.com\nInstagram: @x"
+
+
+def test_normalize_description_right_strips_and_trims():
+    assert normalize_description("  hi there  \n\n  bye  ") == "  hi there\n  bye"
+
+
+def test_normalize_description_all_blank_collapses_to_empty():
+    assert normalize_description("\n \n\t\n") == ""
+
+
+def test_normalize_description_single_line_unchanged():
+    assert normalize_description("just one line") == "just one line"