feat: Add comprehensive documentation suite and reorganize project structure

- Created complete documentation in docs/ directory
- Added PROJECT_OVERVIEW.md with feature highlights and getting started guide
- Added ARCHITECTURE.md with system design and technical details
- Added SECURITY.md with comprehensive security implementation guide
- Added DEVELOPMENT.md with development workflows and best practices
- Added DEPLOYMENT.md with production deployment instructions
- Added API.md with complete REST API documentation
- Added CONTRIBUTING.md with contribution guidelines
- Added CHANGELOG.md with version history and migration notes
- Reorganized all documentation files into docs/ directory for better organization
- Updated README.md with proper documentation links and quick navigation
- Enhanced project structure with professional documentation standards

f_core/f_functions/functions.queue.php

@@ -0,0 +1,69 @@
+<?php
+defined('_ISVALID') or header('Location: /error');
+
+/**
+ * Lightweight queue helpers with Redis fallback to filesystem.
+ */
+
+function queue_redis_client()
+{
+    static $redis = null;
+    if ($redis !== null) return $redis;
+
+    $host = getenv('REDIS_HOST') ?: ($GLOBALS['cfg']['redis_host'] ?? null);
+    $port = (int) (getenv('REDIS_PORT') ?: ($GLOBALS['cfg']['redis_port'] ?? 6379));
+    $db   = (int) (getenv('REDIS_DB') ?: ($GLOBALS['cfg']['redis_db'] ?? 0));
+
+    if (!$host) return $redis = false;
+
+    if (!class_exists('Redis')) return $redis = false;
+
+    try {
+        $r = new Redis();
+        if (!$r->connect($host, $port, 2.0)) return $redis = false;
+        if ($db) $r->select($db);
+        return $redis = $r;
+    } catch (Exception $e) {
+        return $redis = false;
+    }
+}
+
+function queue_enqueue($queue, array $payload)
+{
+    $data = json_encode(['t' => time(), 'payload' => $payload]);
+    if ($r = queue_redis_client()) {
+        return (bool) $r->lPush("q:$queue", $data);
+    }
+    // FS fallback
+    $dir = 'f_data/queues/' . preg_replace('/[^a-z0-9:_-]/i', '_', $queue);
+    if (!is_dir($dir)) @mkdir($dir, 0755, true);
+    $fn = $dir . '/' . microtime(true) . '-' . bin2hex(random_bytes(4)) . '.json';
+    return (bool) @file_put_contents($fn, $data);
+}
+
+function queue_dequeue($queue, $timeout = 2)
+{
+    if ($r = queue_redis_client()) {
+        $res = $r->brPop(["q:$queue"], $timeout);
+        if (is_array($res) && count($res) === 2) {
+            return json_decode($res[1], true);
+        }
+        return null;
+    }
+    // FS fallback (non-blocking, best effort)
+    $dir = 'f_data/queues/' . preg_replace('/[^a-z0-9:_-]/i', '_', $queue);
+    if (!is_dir($dir)) return null;
+    $files = glob($dir . '/*.json');
+    if (!$files) return null;
+    sort($files);
+    $fn = $files[0];
+    $raw = @file_get_contents($fn);
+    @unlink($fn);
+    return $raw ? json_decode($raw, true) : null;
+}
+
+function queue_available()
+{
+    return (bool) queue_redis_client();
+}
+