Extract deno detection logic to separate script

Refactored configure.cmd to call package/scripts/windows/check-deno-in-use.cmd
for better maintainability and testability. The extracted script handles
directory-specific deno.exe process detection on Windows.

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

Author: cderv

configure.cmd

@@ -6,11 +6,6 @@ REM    Variables set dynamically (including being read from a file) should be ev
 REM    using ! ! instead of % %. However, this only allows one level of expansion. Do not
 REM    try to create a variable that derives from a derived variable. It will be empty.
 
-REM First Check that Deno isn't running since this causes weird and confusing errors
-REM find can conflict with one provided in bash with other args so use absolute path
-tasklist /fi "ImageName eq deno.exe" /fo csv 2>NUL | "%WINDIR%/system32/find" /I "deno.exe">NUL
-if "%ERRORLEVEL%"=="0" goto :denoRunning
-
 call package\src\store_win_configuration.bat
 call win_configuration.bat
 
@@ -19,7 +14,27 @@ if NOT DEFINED QUARTO_VENDOR_BINARIES (
 )
 
 if "%QUARTO_VENDOR_BINARIES%" == "true" (
-  RMDIR /S /Q "!QUARTO_DIST_PATH!"
+
+  REM Windows-specific: Check if deno.exe is running before deleting package/dist
+  REM Extracted to package/scripts/windows/check-deno-in-use.cmd for maintainability
+  call package\scripts\windows\check-deno-in-use.cmd "!QUARTO_DIST_PATH!"
+  if "!ERRORLEVEL!"=="1" exit /B 1
+
+  echo Removing package/dist/ directory...
+  RMDIR /S /Q "!QUARTO_DIST_PATH!" 2>NUL
+
+  REM Fallback: Verify deletion succeeded (defense in depth)
+  if exist "!QUARTO_DIST_PATH!" (
+    echo.
+    echo ============================================================
+    echo Error: Could not delete package/dist/ directory
+    echo A process may be holding files open
+    echo ============================================================
+    echo.
+    echo Try closing applications and run configure.cmd again
+    exit /B 1
+  )
+
   MKDIR !QUARTO_BIN_PATH!\tools
   PUSHD !QUARTO_BIN_PATH!\tools
 
@@ -97,9 +112,3 @@ COPY package\typst-gather\target\release\typst-gather.exe "!QUARTO_BIN_PATH!\too
 endlocal & set QUARTO_BIN_DEV=%QUARTO_BIN_PATH%
 
 GOTO :eof
-
-:denoRunning
-
-echo Please ensure no instances of `deno.exe` are running before configuring.
-echo (Deno might be running as an LSP if you have Visual Studio Code open.)
-GOTO :eof

package/scripts/windows/check-deno-in-use.cmd

@@ -0,0 +1,53 @@
+@ECHO OFF
+SETLOCAL ENABLEDELAYEDEXPANSION
+
+REM check-deno-in-use.cmd - Check if deno.exe is running from specified directory
+REM
+REM This script checks if any deno.exe processes are running from the specified
+REM directory path. It is used by configure.cmd to prevent errors when trying to
+REM delete the package/dist directory while deno is still running from it.
+REM
+REM Usage: check-deno-in-use.cmd <directory-path>
+REM
+REM Exit codes:
+REM   0 - No deno process found at path (safe to proceed)
+REM   1 - Deno process found at path (blocking condition)
+REM
+REM This check is directory-specific to support multiple worktrees - it only
+REM blocks if deno.exe is running from the specified directory, not from other
+REM locations (e.g., system deno in PATH or deno from another worktree).
+
+SET "TARGET_PATH=%~1"
+
+REM Validate that a path was provided
+IF "%TARGET_PATH%"=="" (
+  echo Error: No directory path provided
+  echo Usage: check-deno-in-use.cmd ^<directory-path^>
+  EXIT /B 1
+)
+
+REM Remove trailing backslash if present (for consistent path matching)
+IF "!TARGET_PATH:~-1!"=="\" SET "TARGET_PATH=!TARGET_PATH:~0,-1!"
+
+REM Check if deno.exe is running from target path using PowerShell
+REM Uses .StartsWith() for exact prefix matching (not wildcard matching)
+REM Case-insensitive comparison appropriate for Windows file paths
+powershell -NoProfile -Command "if (Get-Process -Name deno -ErrorAction SilentlyContinue | Where-Object { $_.Path -and $_.Path.StartsWith('!TARGET_PATH!', [System.StringComparison]::CurrentCultureIgnoreCase) }) { exit 1 } else { exit 0 }" >NUL 2>&1
+
+IF "!ERRORLEVEL!"=="1" (
+  REM Deno process found - show error message and process list
+  echo.
+  echo ============================================================
+  echo Deno is running from this directory
+  echo Please close Deno processes before running configure.cmd
+  echo ============================================================
+  echo.
+  echo Directory: !TARGET_PATH!
+  echo.
+  echo Deno processes from this directory:
+  powershell -NoProfile -Command "Get-Process -Name deno -ErrorAction SilentlyContinue | Where-Object { $_.Path -and $_.Path.StartsWith('!TARGET_PATH!', [System.StringComparison]::CurrentCultureIgnoreCase) } | Format-Table Id, Path -AutoSize"
+  EXIT /B 1
+)
+
+REM No blocking deno process found
+EXIT /B 0