Add on-demand XAMPP Lite 8.5 installer + Windows time.php support

- install/pqs_install.sql: one-shot installer (creates pqs DB + user, all
  tables as InnoDB, static seed) so a fresh portable XAMPP deploy needs no
  separate migrations. Derived from docs/pqs.sql with engines forced to InnoDB.
- install/README.md: XAMPP Lite 8.5 deployment steps plus fresh-vs-upgrade guidance.
- time.php: OS-aware clock set (PowerShell Set-Date on Windows/XAMPP, sudo date
  on Linux); epoch is int-cast so the exec has no injection.
- .gitignore: exclude the portable xampp_lite_8_5/ stack (not versioned here).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

time.php

@@ -6,13 +6,19 @@
 
 if (isset($_GET['submit'])) {$submit=$_GET['submit'];}else{$submit='';}
 if ($submit=='update'){
+	// Set the machine clock from the browser's time (air-gapped box has no NTP).
+	// $epoch is round(intval(...)) so it is a pure integer -- no shell injection.
+	$epoch = (int) round(((int)($_GET['lct'] ?? 0)) / 1000);
 
-	$settime = $_GET['lct'];
-	$settime2 = round($settime/1000);
-	$settime3 = "@".$settime2;
-
-echo exec("sudo date -s $settime3 > /dev/null &");
-};
+	if (stripos(PHP_OS, 'WIN') === 0) {
+		// Windows / XAMPP: requires Apache (httpd) to be running as administrator.
+		$ps = 'Set-Date -Date ([DateTimeOffset]::FromUnixTimeSeconds(' . $epoch . ').LocalDateTime)';
+		exec('powershell -NoProfile -Command "' . $ps . '"');
+	} else {
+		// Linux: requires the web user to have passwordless sudo for date.
+		exec('sudo date -s @' . $epoch . ' > /dev/null &');
+	}
+}
 
 ?>