AssemblyAI schema: speech_model and speech_models conflict

[Lazare-42]

Bug

The AssemblyAITranscriptionSchema in v0.8.4 exports both speech_model (singular, deprecated) and speech_models (plural, new required array). AssemblyAI's API rejects requests that contain both fields:

speech_model and speech_models cannot be used in the same request.
Use "speech_models": ["model_name"]. — HTTP 400

How to reproduce

const sdk = require('voice-router-dev/field-configs');
const shape = sdk.AssemblyAITranscriptionSchema._zod.def.shape;
console.log('speech_model' in shape);  // true
console.log('speech_models' in shape); // true

When users configure transcription via the DynamicFieldForm (which renders fields from the schema), speech_model gets set as a custom param. The pipeline also sets speech_models as a default/fallback → both are sent → HTTP 400.

Expected behavior

Only speech_models (plural, array) should be in the schema. speech_model (singular) should be removed since AssemblyAI no longer accepts it alongside speech_models.

Workaround

We're filtering out speech_model from custom params and mapping it to speech_models in our submission layer.