feat: complete translation language controls and styling

Tests/ConjureKitTests/TranslationTests.swift

@@ -12,6 +12,8 @@ import Testing
         #expect(body["model"] as? String == "gpt-6-luna")
         #expect(body["input"] as? String == "Good morning")
         #expect(body["store"] as? Bool == false)
+        let instructions = try #require(body["instructions"] as? String)
+        #expect(instructions.contains("from en to ja"))
         return (Data(#"{"status":"completed","output":[{"type":"reasoning"},{"content":[{"type":"output_text","text":"おはようございます"}]}]}"#.utf8),
                 HTTPURLResponse(url: request.url!, statusCode: 200, httpVersion: nil, headerFields: nil)!)
     }
@@ -26,6 +28,20 @@ import Testing
     }
 }
 
+@Test func translationSendsReverseLanguagePairToOpenAI() async throws {
+    let text = try await TranslationAPI.translate(
+        "おはようございます", apiKey: "test-key", sourceLanguage: "ja", targetLanguage: "en"
+    ) { request in
+        let body = try #require(JSONSerialization.jsonObject(with: request.httpBody!) as? [String: Any])
+        let instructions = try #require(body["instructions"] as? String)
+        #expect(instructions.contains("from ja to en"))
+        #expect(body["input"] as? String == "おはようございます")
+        return (Data(#"{"status":"completed","output":[{"content":[{"type":"output_text","text":"Good morning"}]}]}"#.utf8),
+                HTTPURLResponse(url: request.url!, statusCode: 200, httpVersion: nil, headerFields: nil)!)
+    }
+    #expect(text == "Good morning")
+}
+
 @Test @MainActor func translationCommandBackNavigationRestoresSearch() throws {
     _ = NSApplication.shared
     let launcher = LauncherWindowController()