Add reasoning parameter support for Gemini and OpenAI models

VoiceInk/Services/AIEnhancement/AIEnhancementService.swift

@@ -292,13 +292,18 @@ class AIEnhancementService: ObservableObject {
                 ["role": "user", "content": formattedText]
             ]
 
-            let requestBody: [String: Any] = [
+            var requestBody: [String: Any] = [
                 "model": aiService.currentModel,
                 "messages": messages,
                 "temperature": aiService.currentModel.lowercased().hasPrefix("gpt-5") ? 1.0 : 0.3,
                 "stream": false
             ]
 
+            // Add reasoning_effort parameter if the model supports it
+            if let reasoningEffort = ReasoningConfig.getReasoningParameter(for: aiService.currentModel) {
+                requestBody["reasoning_effort"] = reasoningEffort
+            }
+
             request.httpBody = try? JSONSerialization.data(withJSONObject: requestBody)
 
             do {

VoiceInk/Services/AIEnhancement/ReasoningConfig.swift

@@ -0,0 +1,24 @@
+import Foundation
+
+struct ReasoningConfig {
+    static let geminiReasoningModels: Set<String> = [
+        "gemini-2.5-flash",
+        "gemini-2.5-flash-lite"
+    ]
+
+    static let openAIReasoningModels: Set<String> = [
+        "gpt-5",
+        "gpt-5-mini",
+        "gpt-5-nano"
+    ]
+
+    static func getReasoningParameter(for modelName: String) -> String? {
+        if geminiReasoningModels.contains(modelName) {
+            return "low"
+        } else if openAIReasoningModels.contains(modelName) {
+            return "minimal"
+        }
+        return nil
+    }
+}
+