Merge remote-tracking branch 'origin/master' into gitea/feature/end

Resolved conflicts taking origin/master (v0.5.55) as canonical, with local
features re-applied:
- runtime log level (LOG_LEVEL env + dashboard Settings → Logging, applied
  immediately and persisted across restarts)
- free/noAuth provider enable/disable toggle via providerStrategies.enabled
- parallel model testing (Test All Models / Test Selected Keys)

open-sse/providers/registry/mimo-free.js

@@ -1,5 +1,8 @@
+// Xiaomi ended the free MiMo channel ("MiMo free API service has ended").
+// Hidden until/unless a replacement (OAuth MiMo Platform) is wired.
 export default {
   id: "mimo-free",
+  hidden: true,
   priority: 50,
   hasFree: true,
   alias: "mmf",