Merge PR #1628: fix(model-test) route image and STT probes to their real endpoints

Route image model tests to /api/v1/images/generations and STT to
/api/v1/audio/transcriptions instead of forcing all non-embedding
models through chat completions. Adds kind-aware pingModelByKind,
hf->huggingface alias, and silent WAV sample for STT reachability.

Scoped to dashboard/internal model testing only; runtime inference
routing is unchanged.

Author: yicone <yicone@gmail.com>
Closes #1628

open-sse/services/model.js

@@ -29,6 +29,8 @@ const ALIAS_TO_PROVIDER_ID = {
   kimi: "kimi",
   minimax: "minimax",
   "minimax-cn": "minimax-cn",
+  hf: "huggingface",
+  huggingface: "huggingface",
   ds: "deepseek",
   deepseek: "deepseek",
   cmc: "commandcode",