init: projet complet copymail pour Raspberry Pi

Stack: Nginx + PHP 8.2 + MariaDB + Postfix + Dovecot + Samba
- install.sh: script installation automatisé pour RPi OS Bookworm
- Interface web: visionneuse mails + admin (comptes, domaine, dashboard)
- Chaque compte mail génère automatiquement un share Samba
- Processeur cron: extraction pièces jointes via zbateson/mail-mime-parser
- Zéro injection SQL (PDO + prepared statements)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

web/includes/db.php

@@ -0,0 +1,31 @@
+<?php
+
+function db(): PDO {
+    static $pdo = null;
+    if ($pdo !== null) return $pdo;
+
+    $cfg = require __DIR__ . '/../../config.php';
+    $dsn = "mysql:host={$cfg['db_host']};dbname={$cfg['db_name']};charset=utf8mb4";
+    $pdo = new PDO($dsn, $cfg['db_user'], $cfg['db_pass'], [
+        PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION,
+        PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
+        PDO::ATTR_EMULATE_PREPARES   => false,
+    ]);
+    return $pdo;
+}
+
+function cfg(string $key, string $default = ''): string {
+    static $cache = [];
+    if (!isset($cache[$key])) {
+        $st = db()->prepare('SELECT value FROM config WHERE `key` = ?');
+        $st->execute([$key]);
+        $row = $st->fetch();
+        $cache[$key] = $row ? $row['value'] : $default;
+    }
+    return $cache[$key];
+}
+
+function cfg_set(string $key, string $value): void {
+    db()->prepare('INSERT INTO config (`key`, value) VALUES (?, ?) ON DUPLICATE KEY UPDATE value = ?')
+        ->execute([$key, $value, $value]);
+}