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/sambanova.js

@@ -0,0 +1,27 @@
+export default {
+  id: "sambanova",
+  alias: "samba",
+  aliases: ["sambanova-ai"],
+  uiAlias: "samba",
+  hidden: true,
+  display: {
+    name: "SambaNova",
+    icon: "memory",
+    color: "#F97316",
+    textIcon: "SN",
+    website: "https://sambanova.ai",
+    notice: {
+      apiKeyUrl: "https://cloud.sambanova.ai/apis",
+    },
+  },
+  category: "apikey",
+  authType: "apikey",
+  authModes: ["apikey"],
+  transport: {
+    baseUrl: "https://api.sambanova.ai/v1/chat/completions",
+    validateUrl: "https://api.sambanova.ai/v1/models",
+  },
+  models: [
+    { id: "MiniMax-M2.7", name: "MiniMax M2.7", contextLength: 196608 },
+  ],
+};