refactor(stt): share transcription helpers

docs/plugins/sdk-migration.md

@@ -279,7 +279,7 @@ Current bundled provider examples:
   | `plugin-sdk/provider-model-shared` | Shared provider model/replay helpers | `ProviderReplayFamily`, `buildProviderReplayFamilyHooks`, `normalizeModelCompat`, shared replay-policy builders, provider-endpoint helpers, and model-id normalization helpers |
   | `plugin-sdk/provider-catalog-shared` | Shared provider catalog helpers | `findCatalogTemplate`, `buildSingleProviderApiKeyCatalog`, `supportsNativeStreamingUsageCompat`, `applyProviderNativeStreamingUsageCompat` |
   | `plugin-sdk/provider-onboard` | Provider onboarding patches | Onboarding config helpers |
-  | `plugin-sdk/provider-http` | Provider HTTP helpers | Generic provider HTTP/endpoint capability helpers |
+  | `plugin-sdk/provider-http` | Provider HTTP helpers | Generic provider HTTP/endpoint capability helpers, including audio transcription multipart form helpers |
   | `plugin-sdk/provider-web-fetch` | Provider web-fetch helpers | Web-fetch provider registration/cache helpers |
   | `plugin-sdk/provider-web-search-config-contract` | Provider web-search config helpers | Narrow web-search config/credential helpers for providers that do not need plugin-enable wiring |
   | `plugin-sdk/provider-web-search-contract` | Provider web-search contract helpers | Narrow web-search config/credential contract helpers such as `createWebSearchProviderContractFields`, `enablePluginInConfig`, `resolveProviderWebSearchPluginConfig`, and scoped credential setters/getters |

docs/plugins/sdk-overview.md

@@ -137,7 +137,7 @@ explicitly promotes one as public.
     | `plugin-sdk/provider-auth` | `createProviderApiKeyAuthMethod`, `ensureApiKeyFromOptionEnvOrPrompt`, `upsertAuthProfile`, `upsertApiKeyProfile`, `writeOAuthCredentials` |
     | `plugin-sdk/provider-model-shared` | `ProviderReplayFamily`, `buildProviderReplayFamilyHooks`, `normalizeModelCompat`, shared replay-policy builders, provider-endpoint helpers, and model-id normalization helpers such as `normalizeNativeXaiModelId` |
     | `plugin-sdk/provider-catalog-shared` | `findCatalogTemplate`, `buildSingleProviderApiKeyCatalog`, `supportsNativeStreamingUsageCompat`, `applyProviderNativeStreamingUsageCompat` |
-    | `plugin-sdk/provider-http` | Generic provider HTTP/endpoint capability helpers |
+    | `plugin-sdk/provider-http` | Generic provider HTTP/endpoint capability helpers, including audio transcription multipart form helpers |
     | `plugin-sdk/provider-web-fetch-contract` | Narrow web-fetch config/selection contract helpers such as `enablePluginInConfig` and `WebFetchProviderPlugin` |
     | `plugin-sdk/provider-web-fetch` | Web-fetch provider registration/cache helpers |
     | `plugin-sdk/provider-web-search-config-contract` | Narrow web-search config/credential helpers for providers that do not need plugin-enable wiring |

docs/plugins/sdk-provider-plugins.md

@@ -716,6 +716,17 @@ API key auth, and dynamic model resolution.
     as `maxInputImages`, `maxInputVideos`, and `maxDurationSeconds` are not
     enough to advertise transform-mode support or disabled modes cleanly.
 
+    Prefer the shared WebSocket helper for streaming STT providers. It keeps
+    proxy capture, reconnect backoff, close flushing, ready handshakes, audio
+    queueing, and close-event diagnostics consistent across providers while
+    leaving provider code responsible for only the upstream event mapping.
+
+    Batch STT providers that POST multipart audio should use
+    `buildAudioTranscriptionFormData(...)` from
+    `openclaw/plugin-sdk/provider-http` together with the provider HTTP request
+    helpers. The form helper normalizes upload filenames, including AAC uploads
+    that need an M4A-style filename for compatible transcription APIs.
+
     Music-generation providers should follow the same pattern:
     `generate` for prompt-only generation and `edit` for reference-image-based
     generation. Flat aggregate fields such as `maxInputImages`,

docs/plugins/voice-call.md

@@ -155,7 +155,8 @@ Current runtime behavior:
 
 - `streaming.provider` is optional. If unset, Voice Call uses the first
   registered realtime transcription provider.
-- Bundled realtime transcription providers include OpenAI (`openai`) and xAI
+- Bundled realtime transcription providers include Deepgram (`deepgram`),
+  ElevenLabs (`elevenlabs`), Mistral (`mistral`), OpenAI (`openai`), and xAI
   (`xai`), registered by their provider plugins.
 - Provider-owned raw config lives under `streaming.providers.<providerId>`.
 - If `streaming.provider` points at an unregistered provider, or no realtime