fix: Update nginx config to use dynamic DNS resolution

- Replace upstream blocks with resolver directive
- Use variables for backend addresses to avoid startup errors
- Simplify configuration with single server block
- Add health check endpoint

server/api/node_modules/.bin/mkdirp.ps1

@@ -0,0 +1,28 @@
+#!/usr/bin/env pwsh
+$basedir=Split-Path $MyInvocation.MyCommand.Definition -Parent
+
+$exe=""
+if ($PSVersionTable.PSVersion -lt "6.0" -or $IsWindows) {
+  # Fix case when both the Windows and Linux builds of Node
+  # are installed in the same directory
+  $exe=".exe"
+}
+$ret=0
+if (Test-Path "$basedir/node$exe") {
+  # Support pipeline input
+  if ($MyInvocation.ExpectingInput) {
+    $input | & "$basedir/node$exe"  "$basedir/../mkdirp/bin/cmd.js" $args
+  } else {
+    & "$basedir/node$exe"  "$basedir/../mkdirp/bin/cmd.js" $args
+  }
+  $ret=$LASTEXITCODE
+} else {
+  # Support pipeline input
+  if ($MyInvocation.ExpectingInput) {
+    $input | & "node$exe"  "$basedir/../mkdirp/bin/cmd.js" $args
+  } else {
+    & "node$exe"  "$basedir/../mkdirp/bin/cmd.js" $args
+  }
+  $ret=$LASTEXITCODE
+}
+exit $ret