fix: second-round CodeRabbit findings

- verify_compile.cmd: use %%~E to strip quotes from detected Unity path
  (%%E kept surrounding quotes -> double-quoted executable); fail when
  Unity exits nonzero before accepting log markers
- ManageBuild: process subtarget before the active-target short-circuit so
  a 'server' request on <2021.2 errors even when platform is already active
- EncryptedFileKeyStore: correct comment (netstandard2.0, not 2.1)

Author: RoyougiShiki

MCPForUnity/Editor/Security/SecureKeyStore/EncryptedFileKeyStore.cs

@@ -103,7 +103,7 @@ private void DeriveKeys(out byte[] encKey, out byte[] macKey)
                 Buffer.BlockCopy(material, 32, macKey, 0, 32);
             }
 #else
-            // Unity 2020.3 (netstandard2.1) has no 4-arg Rfc2898DeriveBytes overload, so
+            // Unity 2020.3 (netstandard2.0 profile) has no 4-arg Rfc2898DeriveBytes overload, so
             // implement PBKDF2-HMAC-SHA256 (RFC 2898) manually to keep key derivation
             // byte-identical with the 2021.2+ path (a 3-arg SHA1 derivation would make
             // existing ciphertext fail MAC validation).

MCPForUnity/Editor/Tools/ManageBuild.cs

@@ -232,15 +232,8 @@ private static object HandlePlatform(ToolParams p)
                 return new ErrorResponse(
                     $"Platform '{target}' is not installed. Install it via Unity Hub.");
 
-            if (EditorUserBuildSettings.activeBuildTarget == target)
-                return new SuccessResponse("Already on this platform.", new
-                {
-                    target = target.ToString()
-                });
-
-            // Capture previous target before switching
-            string previousTarget = EditorUserBuildSettings.activeBuildTarget.ToString();
-
+            // Process subtarget before the active-target short-circuit so a "server"
+            // request on Unity < 2021.2 errors out even when the platform is already active.
             string subtargetStr = p.Get("subtarget");
             if (!string.IsNullOrEmpty(subtargetStr))
             {
@@ -259,6 +252,15 @@ private static object HandlePlatform(ToolParams p)
 #endif
             }
 
+            if (EditorUserBuildSettings.activeBuildTarget == target)
+                return new SuccessResponse("Already on this platform.", new
+                {
+                    target = target.ToString()
+                });
+
+            // Capture previous target before switching
+            string previousTarget = EditorUserBuildSettings.activeBuildTarget.ToString();
+
             // SwitchActiveBuildTarget is synchronous — blocks until reimport completes
             EditorUserBuildSettings.SwitchActiveBuildTarget(group, target);
 

TestProjects/Unity2020Compat/verify_compile.cmd

@@ -24,7 +24,7 @@ if not "%~1"=="" (
         "C:\Program Files\Unity\Hub\Editor\2020.3.*\Editor\Unity.exe"
         "%ProgramFiles%\Unity\Hub\Editor\2020.3.*\Editor\Unity.exe"
     ) do (
-        if not defined UNITY_EXE if exist %%E set "UNITY_EXE=%%E"
+        if not defined UNITY_EXE if exist %%~E set "UNITY_EXE=%%~E"
     )
 )
 
@@ -45,6 +45,11 @@ del /q "%LOG_FILE%" 2>nul
 "%UNITY_EXE%" -batchmode -nographics -quit -projectPath "%PROJECT_DIR%" -logFile "%LOG_FILE%"
 set "UNITY_STATUS=%ERRORLEVEL%"
 
+if not "%UNITY_STATUS%"=="0" (
+    echo [verify] FAILED: Unity exited with status %UNITY_STATUS%.
+    exit /b 1
+)
+
 if not exist "%LOG_FILE%" (
     echo [verify] No log file produced (Unity may have failed to start).
     exit /b 1