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/translator/formats/gemini.js

@@ -7,7 +7,13 @@ import { OPENAI_BLOCK } from "../schema/index.js";
 export const UNSUPPORTED_SCHEMA_CONSTRAINTS = [
   // Basic constraints (not supported by Gemini API)
   "minLength", "maxLength", "exclusiveMinimum", "exclusiveMaximum",
-  "minItems", "maxItems", "format",
+  "minItems", "maxItems", "format", "multipleOf",
+  // Array keywords the Gemini schema proto has no field for. Agent tool
+  // schemas set these routinely, and one occurrence rejects the whole request
+  // with "Unknown name ...: Cannot find field".
+  "uniqueItems", "contains",
+  // 2020-12 keywords with no Gemini equivalent
+  "unevaluatedProperties", "unevaluatedItems", "contentSchema",
   // Claude rejects these in VALIDATED mode
   "default", "examples",
   // JSON Schema meta keywords
@@ -353,6 +359,19 @@ export function cleanJSONSchemaForAntigravity(schema) {
   function addPlaceholders(obj) {
     if (!obj || typeof obj !== "object") return;
 
+    // Empty schema {} (no type, no properties) after $ref removal — treat as object with placeholder
+    if (Object.keys(obj).length === 0) {
+      obj.type = "object";
+      obj.properties = {
+        reason: {
+          type: "string",
+          description: "Brief explanation of why you are calling this tool"
+        }
+      };
+      obj.required = ["reason"];
+      return;
+    }
+
     if (obj.type === "object") {
       if (!obj.properties || Object.keys(obj.properties).length === 0) {
         obj.properties = {