Wire the onboarding burst to its quality-aware selection and a stronger model:
- main.go onboard uses OnboardBurstVideoIDs (junk-avoiding) instead of pure
newest-first, bounded by MinVideoSeconds / OnboardMaxVideoSeconds.
- buildBurstProcessor builds a burst-only summarizer chain led by the onboard
model (burstChainModels: onboard -> standard ADR-022 chain, deduped, NDA lever
intact), over the same store/cache/sink. Collapses onto the shared Processor
when the onboard model is empty/equal-to-primary or config is incomplete.
- summarizerEndpoint + newYouTubeSource extracted so standard and burst wiring
share one definition.
- Remove now-superseded NewestUnsummarizedVideoIDs: OnboardBurstVideoIDs(.,0,0)
is identical pure-newest behaviour and its test covers RLS + ordering.