build: remove legacy UpdateGameDlls target and simplify PS1 script

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

UpdateGameDlls.ps1

@@ -130,34 +130,7 @@ if (-not $publicizer) {
 }
 
 # ---------------------------------------------------------------------------
-# 5. Acquire an exclusive file lock so that concurrent MSBuild nodes (triggered
-#    by the !Exists fallback condition) cannot write the DLLs simultaneously.
-#    The lock is released automatically in the finally block.
-# ---------------------------------------------------------------------------
-$lockPath   = Join-Path $OUTPUT_DIR '.update.lock'
-$lockStream = $null
-try {
-    # Retry loop: wait up to 60 s for the lock (another node may be updating)
-    $deadline = [DateTime]::UtcNow.AddSeconds(60)
-    while ($true) {
-        try {
-            $lockStream = [System.IO.File]::Open(
-                $lockPath,
-                [System.IO.FileMode]::OpenOrCreate,
-                [System.IO.FileAccess]::ReadWrite,
-                [System.IO.FileShare]::None)
-            break   # lock acquired
-        } catch [System.IO.IOException] {
-            if ([DateTime]::UtcNow -ge $deadline) {
-                Write-Warning 'UpdateGameDlls: Timed out waiting for lock; skipping DLL update.'
-                exit 0
-            }
-            Start-Sleep -Milliseconds 200
-        }
-    }
-
-# ---------------------------------------------------------------------------
-# 6. For each DLL: compare timestamps, publicize if game copy is newer
+# 5. For each DLL: compare timestamps, publicize if game copy is newer
 # ---------------------------------------------------------------------------
 $updated = 0
 foreach ($dll in $DSP_DLLS) {
@@ -203,8 +176,3 @@ if ($updated -gt 0) {
 } else {
     Write-Host 'UpdateGameDlls: All DLLs are up-to-date.'
 }
-
-} finally {
-    # Release the exclusive lock regardless of success or failure
-    if ($lockStream) { $lockStream.Close() }
-}