When users select "Other" to provide freeform input, Claude re-prompts
with another AskUserQuestion instead of dropping to plain text. This
loops 2-3 times before finally accepting freeform input.
Add explicit freeform escape rule to questioning.md reference, and
update new-milestone.md and discuss-phase.md to switch to plain text
when users signal freeform intent.
Closes#778
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>