Channels enriched before InnerTube existed (partial coverage, e.g. CaseyNeistat
36, Good Mythical MORE 25) were locked behind the 24h coverage gate and would
never reach the full ~240-date catalog on their own. Tag each enrichment row
with the source ('innertube'|'fallback'); legacy rows (method NULL after the
additive migration) bypass the gate ONCE so they re-enrich and upgrade, then
settle under the normal window. Non-destructive: existing follows, wished videos
(24), and cached dates (1176) are untouched — only coverage refreshes on next
open/sweep. Migration is additive (method TEXT); regression test added.
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