fix: stop grouping HF/ModelScope models by repository

A repository is not a model identity: collection repos on Hugging Face
and ModelScope host many unrelated models, which were wrongly shown as
versions of each other.

- Hugging Face models no longer auto-group (the Hub exposes no
  site-native model id)
- ModelScope models group by the site's native published-model id
  (MuseInfo modelVersion.modelId), extracted during enrichment and
  persisted on the sidecar as source_model_id/source_version_id;
  unenriched models stay standalone instead of collapsing a whole repo
  into one group
- TensorArt grouping unchanged (its URL id is already model-level)
- Frontend group-key derivation mirrors the new backend semantics

static/js/utils/modelSourceHelpers.js

@@ -6,8 +6,7 @@
  * support AI metadata enrichment.
  *
  * Models loaded from an older cache may only carry the legacy `hf_url`
- * field; every helper here falls back to it, and to the legacy
- * `hf:user/repo` group key shape.
+ * field; every helper here falls back to it.
  */
 
 import { translate } from './i18nHelpers.js';
@@ -17,6 +16,9 @@ export const MODEL_SOURCES = [
     platform: 'huggingface',
     label: 'Hugging Face',
     groupPrefix: 'hf',
+    // A repository hosts many unrelated models and the site exposes no
+    // model-level identity, so HF models never auto-group.
+    groupKey: 'none',
     supportsEnrichment: true,
     supportsDownload: true,
     defaultRevision: 'main',
@@ -36,6 +38,9 @@ export const MODEL_SOURCES = [
     platform: 'modelscope',
     label: 'ModelScope',
     groupPrefix: 'ms',
+    // Group by the site-native published-model id (`source_model_id`),
+    // recorded by enrichment — the repo id is not a model identity.
+    groupKey: 'modelId',
     supportsEnrichment: true,
     supportsDownload: true,
     defaultRevision: 'master',
@@ -56,6 +61,7 @@ export const MODEL_SOURCES = [
     platform: 'modelscope-ai',
     label: 'ModelScope (International)',
     groupPrefix: 'msai',
+    groupKey: 'modelId',
     supportsEnrichment: true,
     supportsDownload: true,
     defaultRevision: 'master',
@@ -73,6 +79,8 @@ export const MODEL_SOURCES = [
     platform: 'tensorart',
     label: 'TensorArt',
     groupPrefix: 'ta',
+    // The numeric id in a TensorArt URL already identifies a single model.
+    groupKey: 'repo',
     supportsEnrichment: false,
     supportsDownload: false,
     defaultRevision: '',
@@ -152,11 +160,21 @@ export function getModelSourceInfo(model) {
 
 /**
  * Version-group key for a model, matching the backend's `_extract_group_key`.
- * Returns `''` when the model has no external source.
+ * Returns `''` when the model has no external source, or when its source has
+ * no reliable model identity (Hugging Face, or a ModelScope model that has
+ * not been enriched with the site-native `source_model_id` yet).
  */
 export function getModelSourceGroupKey(model) {
   const info = getModelSourceInfo(model);
-  if (!info || !info.sourceId) return '';
+  if (!info) return '';
+  const strategy = info.groupKey || 'repo';
+  if (strategy === 'none') return '';
+  if (strategy === 'modelId') {
+    const modelId =
+      model && typeof model.source_model_id === 'string' ? model.source_model_id.trim() : '';
+    return modelId ? `${info.groupPrefix}:${modelId}` : '';
+  }
+  if (!info.sourceId) return '';
   return `${info.groupPrefix}:${info.sourceId}`;
 }