Voice (Retell)

Retell call-lifecycle webhook: every ended/analyzed call becomes a contact + call record (see ingest.py for the notification posture).

``call_ended`` writes the base record; ``call_analyzed`` upserts the summary and the post-call capture onto the same row (idempotent by provider call id). The capture (design doc P22) prefers the post-call analysis fields (``call_analysis.custom_analysis_data`` — whole-transcript extraction) and falls back to what the mid-call extract tool collected (``collected_dynamic_variables``); both are only present on ``call_analyzed``. Always 200 — Retell retries 5xxs and duplicates are wasted work.

Resolve dialed number → business, inject its context as dynamic variables.

Retell custom-function endpoint: dispatch mid-call tool calls.

Retell POSTs ``{"name": ..., "args": {...}, "call": {...}}`` signed with the same ``x-retell-signature`` scheme as the inbound webhook (same key). Tenant identity comes from ``call.metadata.business_id`` — the value OUR inbound webhook planted, which is why it's trustworthy (design doc §6.4). The response body is a plain JSON string: Retell hands it to the agent's LLM verbatim, so failures are honest instruction strings, never 5xx.