fix(android): 修复rebuild选项删除aar后未重建的bug

将rebuild参数解析移到tsslib.aar存在检查之前，
确保删除aar后能触发gomobile重新编译。

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/mpc-system/services/service-party-android/build-apk.bat

@@ -75,6 +75,20 @@ echo [INFO] Using SDK from local.properties
 type local.properties
 echo.
 
+:: Parse rebuild argument early - must happen BEFORE checking tsslib.aar
+set REBUILD_REQUESTED=0
+if "%1"=="rebuild" (
+    set REBUILD_REQUESTED=1
+    echo [INFO] Rebuild requested - deleting tsslib.aar to recompile Go code...
+    if exist "app\libs\tsslib.aar" (
+        del /f "app\libs\tsslib.aar"
+        echo [INFO] tsslib.aar deleted, will be rebuilt
+    ) else (
+        echo [INFO] tsslib.aar not found, will be built fresh
+    )
+    echo.
+)
+
 :: Check and build tsslib.aar if needed
 if not exist "app\libs\tsslib.aar" (
     echo [INFO] tsslib.aar not found, attempting to build TSS library...
@@ -186,17 +200,9 @@ if "%1"=="clean" set BUILD_TYPE=clean
 if "%1"=="rebuild" set BUILD_TYPE=rebuild
 if "%1"=="help" goto :show_help
 
-:: Handle rebuild - delete tsslib.aar to force recompilation of Go code
+:: Handle rebuild - aar deletion already done above, just set build type
 if "%BUILD_TYPE%"=="rebuild" (
-    echo [INFO] Rebuild requested - deleting tsslib.aar to recompile Go code...
-    if exist "app\libs\tsslib.aar" (
-        del /f "app\libs\tsslib.aar"
-        echo [INFO] tsslib.aar deleted, will be rebuilt
-    ) else (
-        echo [INFO] tsslib.aar not found, will be built fresh
-    )
     set BUILD_TYPE=all
-    echo.
 )
 
 :: Show build type