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/components/shared/ModelCard.js

@@ -522,7 +522,7 @@ export function createModelCard(model, modelType) {
         card.dataset.modelId = modelId;
     } else {
         // For externally-sourced models, derive a group key from the source
-        // URL for version grouping (hf:user/repo, ms:user/repo, ta:<id>).
+        // identity for version grouping (ms:<model_id>, ta:<id>).
         const sourceGroupKey = getModelSourceGroupKey(model);
         if (sourceGroupKey) {
             card.dataset.modelId = sourceGroupKey;

static/js/components/shared/ModelVersionsTab.js

@@ -994,9 +994,9 @@ export function initVersionsTab({
             renderErrorState(container, translate('modals.model.versions.missingModelId', {}, 'This model is missing a Civitai model id.'));
             return;
         }
-        // External source group keys (e.g. "hf:user/repo", "ms:user/repo",
-        // "ta:8278...") are not real CivitAI model IDs — skip the remote API
-        // call and show a helpful message instead.
+        // External source group keys (e.g. "ms:12345", "ta:8278...") are
+        // not real CivitAI model IDs — skip the remote API call and show a
+        // helpful message instead.
         const sourceGroup = parseModelSourceGroupKey(modelId);
         if (sourceGroup) {
             controller.isLoading = false;