Gate vendor.cmd cache wipe behind QUARTO_SKIP_DENO_CACHE_WIPE

Windows counterpart to the vendor.sh change. Behavior matches:
default wipes, QUARTO_SKIP_DENO_CACHE_WIPE=1 preserves.

Author: cderv

package/scripts/vendoring/vendor.cmd

@@ -18,9 +18,12 @@ IF NOT DEFINED DENO_DIR (
 
 ECHO Revendoring quarto dependencies
 
-REM remove deno_cache directory first
+REM remove deno_cache directory first, unless explicitly told to preserve
+REM (CI sets QUARTO_SKIP_DENO_CACHE_WIPE=1 so a restored cache survives vendor.cmd)
 IF EXIST "!DENO_DIR!" (
-  RMDIR /S /Q "!DENO_DIR!"
+  IF NOT "!QUARTO_SKIP_DENO_CACHE_WIPE!"=="1" (
+    RMDIR /S /Q "!DENO_DIR!"
+  )
 )
 
 PUSHD "!QUARTO_SRC_PATH!"