feat: système multi-tenant (familles + inscription + invitations)

- docker/init/00-setup.sql : meta DB househub_meta (families + users) + grants
- docker/schema_family.sql : template DB par famille (toutes les pf_* tables)
- docker-compose.yml : MYSQL_DATABASE=househub_meta, init dir monté
- includes/meta_db.php : PDO vers househub_meta
- includes/db.php : connexion dynamique vers la DB famille (session)
- login.php : auth via meta DB + family_db en session + lien inscription
- register.php : inscription + création famille OU rejoindre via code
- invite.php : voir son code d'invitation + membres de l'espace

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

includes/db.php

@@ -3,26 +3,38 @@ if (file_exists(__DIR__ . '/config.php')) {
     require_once __DIR__ . '/config.php';
 }
 
-$host    = getenv('DB_HOST') ?: 'househub-db';
-$db      = getenv('DB_NAME') ?: 'househub';
-$user    = getenv('DB_USER') ?: 'househub';
-$pass    = getenv('DB_PASS') ?: 'changeme';
-$charset = 'utf8mb4';
+if (session_status() === PHP_SESSION_NONE) {
+    session_start();
+}
 
-$dsn = "mysql:host=$host;dbname=$db;charset=$charset";
+$host = getenv('DB_HOST') ?: 'househub-db';
+$user = getenv('DB_USER') ?: 'househub';
+$pass = getenv('DB_PASS') ?: 'changeme';
+$db   = $_SESSION['family_db'] ?? null;
 
-$options = [
-    PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION,
-    PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
-    PDO::ATTR_EMULATE_PREPARES   => false,
-    PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES utf8mb4 COLLATE utf8mb4_general_ci",
-    PDO::ATTR_TIMEOUT            => 30,
-];
+if (!$db) {
+    $current = basename($_SERVER['PHP_SELF'] ?? '');
+    if (!in_array($current, ['login.php', 'register.php'])) {
+        header('Location: /login.php');
+        exit;
+    }
+    return;
+}
 
 try {
-    $pdo = new PDO($dsn, $user, $pass, $options);
+    $pdo = new PDO(
+        "mysql:host=$host;dbname=$db;charset=utf8mb4",
+        $user, $pass,
+        [
+            PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION,
+            PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
+            PDO::ATTR_EMULATE_PREPARES   => false,
+            PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES utf8mb4 COLLATE utf8mb4_general_ci",
+            PDO::ATTR_TIMEOUT            => 30,
+        ]
+    );
     $pdo->exec("SET collation_connection = utf8mb4_general_ci");
 } catch (\PDOException $e) {
-    die("Erreur de connexion BDD : " . $e->getMessage());
+    die("Erreur connexion BDD famille : " . $e->getMessage());
 }
 ?>

includes/meta_db.php

@@ -0,0 +1,21 @@
+<?php
+// Connexion à la base meta (gestion des familles et utilisateurs)
+$meta_host = getenv('DB_HOST') ?: 'househub-db';
+$meta_db   = 'househub_meta';
+$meta_user = getenv('DB_USER') ?: 'househub';
+$meta_pass = getenv('DB_PASS') ?: 'changeme';
+
+try {
+    $meta_pdo = new PDO(
+        "mysql:host=$meta_host;dbname=$meta_db;charset=utf8mb4",
+        $meta_user,
+        $meta_pass,
+        [
+            PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION,
+            PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
+            PDO::ATTR_EMULATE_PREPARES   => false,
+        ]
+    );
+} catch (\PDOException $e) {
+    die(json_encode(['error' => 'Meta DB unavailable: ' . $e->getMessage()]));
+}