feat(settings): filename templates for download and bulk rename (#1071)

Add per-model-type filename templates ({model_name}, {version_name},
{base_model}, {author}, {first_tag}, {hash_short}, {original_name}) so
downloaded files get informative names instead of e.g. V1.safetensors.
Empty template keeps the current filename (opt-in, off by default).

- apply template automatically after downloads; rename conflicts keep
  the original name and never fail the download
- record original_file_name in metadata on rename for traceability
- bulk apply via GET|POST /api/lm/{prefix}/apply-filename-template with
  WebSocket progress, sharing the auto-organize lock
- settings UI lives in the new Organization tab with validation, live
  preview, and per-type 'apply to library' actions

static/js/api/apiConfig.js

@@ -122,6 +122,9 @@ export function getApiEndpoints(modelType) {
         autoOrganize: `/api/lm/${modelType}/auto-organize`,
         autoOrganizeProgress: `/api/lm/${modelType}/auto-organize-progress`,
 
+        // Filename template operations
+        applyFilenameTemplate: `/api/lm/${modelType}/apply-filename-template`,
+
         // Model-specific endpoints (will be merged with specific configs)
         specific: {}
     };