fix: remove non-functional Krisp smartEndpointingPlan provider

[chiranjeet-vapi]

Summary

smartEndpointingPlan.provider: "krisp" is documented in voice-pipeline-configuration.mdx as a working configuration option, but it isn't a valid value in the API today. The smartEndpointingPlan schema only accepts vapi, livekit, and custom-endpointing-model (verified against https://api.vapi.ai/api-json, checked 2026-09-25 — the field's own schema description reads "Pick between Vapi smart endpointing, LiveKit, or custom endpointing model (or nothing)"). Setting provider: "krisp" returns:

400: "startSpeakingPlan.smartEndpointingPlan.provider must be one of the
following values: vapi, livekit, custom-endpointing-model"

• Removes the four passages presenting krisp as a working smartEndpointingPlan provider (Providers tab bullet, "when to use" bullet, a full "Krisp threshold configuration" section with a code example, and a full "Audio-based endpointing (Krisp example)" section with a code example).
• Adds a schema-accurate "Custom endpointing model configuration" section for custom-endpointing-model, a provider value that was already valid in the API but had no documented example anywhere on the page. Example request/response shape is taken directly from the CustomEndpointingModelSmartEndpointingPlan schema description, nothing invented.

Test plan

• Confirmed krisp is not in the live API spec's smartEndpointingPlan enum (vapi, livekit, custom-endpointing-model only)
• Confirmed no remaining krisp mentions in the changed file
• Confirmed no other files in the repo were touched

[lightsage-app]

Lightsage docs evals

Waiting for the staging docs URL before running evals.

Lightsage will start the selected PR evals automatically when GitHub reports a successful docs deployment for this PR. This usually happens within 15 minutes.

Commit: f47acde
Status: waiting for staging docs URL