fix(usage-control): enrich usageControl from CivitAI by-hash API for all model types

The model-level API (GET /api/v1/models/{id}) does not include usageControl
on version entries, causing generation-only models to show as downloadable.

Backend changes:
- Add get_model_versions_by_hashes() to CivitaiClient (POST by-hash batch)
- Propagate through all provider classes including RateLimitRetryingProvider
- Add _enrich_version_entries() pipeline: extract SHA256 from files[].hashes,
  batch-call by-hash endpoint, inject usageControl+earlyAccessEndsAt in-place
- Wire enrichment into both bulk (_fetch_model_versions_bulk) and individual
  (_refresh_single_model) refresh paths
- Fix _build_record_from_remote dropping usage_control field
- Fix POST by-hash request format (plain JSON array, not {hashes:[...]} object)

Frontend changes:
- Fix disabled download button tooltip: wrap in <span> since HTML title
  attribute does not fire on disabled elements

static/css/components/lora-modal/versions.css

@@ -387,6 +387,10 @@
     cursor: not-allowed;
 }
 
+.version-action-disabled-wrapper {
+    display: inline-flex;
+}
+
 .versions-loading-state,
 .versions-empty,
 .versions-error {