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)

tests/package.json

@@ -5,8 +5,8 @@
   "type": "module",
   "description": "Unit tests for 9router embeddings endpoint",
   "scripts": {
-    "test": "NODE_PATH=/tmp/node_modules /tmp/node_modules/.bin/vitest run --reporter=verbose",
-    "test:watch": "NODE_PATH=/tmp/node_modules /tmp/node_modules/.bin/vitest --reporter=verbose"
+    "test": "vitest run --reporter=verbose",
+    "test:watch": "vitest --reporter=verbose"
   },
   "devDependencies": {
     "vitest": "^4.0.0"