Fix mid-call silence: keep momentum after acknowledgments

A caller gave their insurance; AVA replied with a bare acknowledgment ("staff
will verify your coverage") and stopped, with no follow-up question. Both sides
then waited -> dead air (pipeline idle, no GPU/LLM activity, matching flat
memory/wattage). Caller had to break the silence with "what questions do you
have?". Root cause: the one-sentence brevity rule made AVA end a booking turn on
a dead-end statement.

Fix: prompt now requires, until the booking is complete, that every turn end
with the next question — acknowledgment + next question in the same turn (e.g.
insurance ack -> immediately ask day/time). Verified 4/4. Documented in CLAUDE.md.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

CLAUDE.md

@@ -270,6 +270,11 @@ time, leading the call rather than waiting on the caller. Fixed order:
 confirmed" — everything is a request staff confirm on callback. **Insurance:** never say "we
 accept/take" a plan (or invent one) — just note what the caller said; staff verify.
 
+**Keep momentum (prevents mid-call silence):** until the booking is complete, every turn ends
+with the next question. A bare acknowledgment with no question (e.g. just "staff will verify
+your coverage") deadlocks the call — both sides wait, the pipeline goes idle (no GPU/LLM
+activity), and the caller hears silence. So acknowledgment + next question go in the same turn.
+
 **Closing is gated:** the word "Goodbye" ends the call (triggers `EndCallProcessor` → hang-up),
 so it is never said in the same turn as confirming details and never before the anything-else
 question — only after the caller says they need nothing more.