perf(R): avoid FFI call when ARM64 R is correctly configured

Check isX64R first to short-circuit when R is ARM64 (the correct setup).
This avoids unnecessary IsWow64Process2 FFI call in the common case.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: cderv

src/core/knitr.ts

@@ -82,7 +82,7 @@ function checkWindowsArmR(platform: string | undefined): void {
 
   const isX64R = platform.includes("x86_64") || platform.includes("i386");
 
-  if (isWindowsArm() && isX64R) {
+  if (isX64R && isWindowsArm()) {
     throw new WindowsArmX64RError(
       "x64 R detected on Windows ARM.\n\n" +
         "x64 R runs under emulation and is not reliable for Quarto.\n" +