Fix config check test. Improve log level.

Author: mobile-ar

Sources/XcodeAssistantCopilotServer/Services/CopilotAPIService.swift

@@ -186,7 +186,7 @@ public struct CopilotAPIService: CopilotAPIServiceProtocol {
             logger.error("Copilot API error response (HTTP \(response.statusCode)), body length=\(body.count) chars")
             logger.error("Copilot API error body: \(body)")
             if let data = body.data(using: .utf8) {
-                logger.error("Copilot API error body (pretty-printed):\n\(data.prettyPrintedJSON)")
+                logger.debug("Copilot API error body (pretty-printed):\n\(data.prettyPrintedJSON)")
             }
             throw CopilotAPIError.requestFailed(statusCode: response.statusCode, body: body)
         }

Tests/XcodeAssistantCopilotServerTests/Configuration/ConfigurationLoaderTests.swift

@@ -1127,6 +1127,8 @@ private func makeLoader(logger: MockLogger = MockLogger()) -> (ConfigurationLoad
     let (directory, configPath, cleanup) = makeTempConfigDir()
     defer { cleanup() }
 
+    try FileManager.default.createDirectory(atPath: directory, withIntermediateDirectories: true)
+
     let partialJSON = """
     {
       "mcpServers": {},
@@ -1161,6 +1163,7 @@ private func makeLoader(logger: MockLogger = MockLogger()) -> (ConfigurationLoad
     let (directory, configPath, cleanup) = makeTempConfigDir()
     defer { cleanup() }
 
+    try FileManager.default.createDirectory(atPath: directory, withIntermediateDirectories: true)
     try ConfigurationLoader.defaultConfigJSON.write(toFile: configPath, atomically: true, encoding: .utf8)
 
     let originalData = try Data(contentsOf: URL(fileURLWithPath: configPath))
@@ -1185,6 +1188,8 @@ private func makeLoader(logger: MockLogger = MockLogger()) -> (ConfigurationLoad
     let (directory, configPath, cleanup) = makeTempConfigDir()
     defer { cleanup() }
 
+    try FileManager.default.createDirectory(atPath: directory, withIntermediateDirectories: true)
+
     let partialJSON = """
     {
       "mcpServers": {},