Filter to channels you haven't personally tagged in the channel manager
(no user-owned ChannelTag; auto language/topic tags don't count):
- Feed: a "No tag" sentinel in the "Your tags" sidebar combobox (exclusive
with real tag picks) + a removable "Untagged" chip; new `untagged` bool
feed param / `notag` URL key, persisted + coerced on every filter path.
- Channel manager: a virtual "No tag" chip in the tag-chip row filters the
table to untagged channels (client-side, shared NO_TAG_SENTINEL).
Backend `untagged` is a plain channel-level narrowing, so feed_summary keeps
it applied in the base pass — the count/facet lockstep holds with no mirror.
Note: item E (per-tag counts) and item D (Any/All toggle) were already
shipped; S1 delivers only item B.
- list_channels no longer computes the Normal/Shorts/Live aggregation the
frontend stopped reading when R14 dropped the N/S/L table column; the dead
ManagedChannel.count_* fields are gone too.
- Immediate "get full history" backfill now coordinates with the paced
scheduler via a small in-flight set: capped at 2 concurrent + per-channel
dedup, and run_deep_backfill skips a channel an immediate backfill owns —
killing the cursor race and bounding the quota-drain burst, without losing
the speed win.
- Add test_channel_backfill.py: the channelDetail N/S/L counts + the guard's
no-op / cap / scheduler-skip behaviour.
- Inline the syncedChannels useMemo (its dep is a fresh array each render, so
it never cached); fix the stale "~2-min ticks" comment (it's 10 minutes).
- applySyncFilter: the fully/needsFull/all predicate the top chips drive
(moved off the retired Sync column) — guards which channels show.
- DataTable fixedLayout: asserts the colgroup + table-fixed appear only
when opted in, with widths on fixed columns and none on fluid ones.
peter