After picking "Other…" from the channel picker, today's flow drops the
user straight into a free-text prompt with no way back. Replace it with
a brightSelect that offers either "Type the channel name" (existing
behavior) or "← Back to channel selection" — same back-affording pattern
the channel sub-flows already use.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
