dev: add live-reload development server

public/live-reload.php

@@ -0,0 +1,56 @@
+<?php
+/**
+ * Simple live-reload endpoint for development.
+ * Polls file mtimes across all source directories and returns
+ * whether anything changed since last check.
+ *
+ * Only active when served by PHP's built-in CLI server.
+ */
+
+if (php_sapi_name() !== 'cli-server') {
+    http_response_code(403);
+    exit;
+}
+
+header('Content-Type: application/json');
+
+$root = dirname(__DIR__);
+
+$watchDirs = [
+    $root . '/public',
+    $root . '/includes',
+    $root . '/lib',
+    $root . '/config',
+];
+
+$watchExts = ['php', 'css', 'js', 'html'];
+
+$hash = '';
+foreach ($watchDirs as $dir) {
+    if (!is_dir($dir)) continue;
+    $it = new RecursiveIteratorIterator(
+        new RecursiveDirectoryIterator($dir, RecursiveDirectoryIterator::SKIP_DOTS)
+    );
+    foreach ($it as $file) {
+        if (in_array($file->getExtension(), $watchExts)) {
+            $hash .= $file->getMTime() . '|' . $file->getPathname() . "\n";
+        }
+    }
+}
+
+$fingerprint = md5($hash);
+$stateFile = sys_get_temp_dir() . '/posterg-live-reload.txt';
+
+$prev = file_exists($stateFile) ? file_get_contents($stateFile) : null;
+// First visit: write baseline, don't fire a reload
+if ($prev === null) {
+    file_put_contents($stateFile, $fingerprint);
+    $changed = false;
+} else {
+    $changed = $fingerprint !== $prev;
+    if ($changed) {
+        file_put_contents($stateFile, $fingerprint);
+    }
+}
+
+echo json_encode(['changed' => $changed]);