Phase 2 sub-commit 1: Doctrine ORM 3 + Migrations + SQLite

Skeleton gains Doctrine ORM 3.6 (with DoctrineBundle 3.x and Migrations
4.x), pointed at a SQLite file under var/data.sqlite. Apps move to
Postgres/MySQL by overriding DATABASE_URL in .env.local.

config/packages/doctrine.yaml registers the symfony/uid UuidType so
Phase 2 sub-commit 4's UUIDv7 default works without per-app config,
and pre-wires the App\Entity attribute mapping under src/Entity/ for
the maker to drop entities into.

Bundle gains an optional doctrine/dbal Connection via Autowire; when
present, bridge:doctor adds a "Database reachable" SELECT-1 probe.
The bundle still installs cleanly without doctrine/dbal — apps that
opt out get a doctor table without the database row.

Verified: `bin/console bridge:doctor` is all green against a fresh
SQLite. composer quality (PHPStan + cs-fixer + PHPUnit) stays green.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

framework/php/src/Command/BridgeDoctorCommand.php

@@ -4,6 +4,7 @@ declare(strict_types=1);
 
 namespace PhpQml\Bridge\Command;
 
+use Doctrine\DBAL\Connection;
 use Symfony\Component\Console\Attribute\AsCommand;
 use Symfony\Component\Console\Command\Command;
 use Symfony\Component\Console\Input\InputInterface;
@@ -30,6 +31,9 @@ final class BridgeDoctorCommand extends Command
         private readonly string $mercurePublisherKey,
         #[Autowire('%env(default::MERCURE_SUBSCRIBER_JWT_KEY)%')]
         private readonly string $mercureSubscriberKey,
+        // Optional: present only if the application installs doctrine/dbal.
+        #[Autowire(service: 'doctrine.dbal.default_connection')]
+        private readonly ?Connection $dbConnection = null,
     ) {
         parent::__construct();
     }
@@ -68,6 +72,15 @@ final class BridgeDoctorCommand extends Command
                 'Set MERCURE_SUBSCRIBER_JWT_KEY in .env.local; or rely on the Caddy `anonymous` directive in dev mode.'],
         ];
 
+        if (null !== $this->dbConnection) {
+            try {
+                $this->dbConnection->fetchOne('SELECT 1');
+                $checks[] = ['Database reachable', true, ''];
+            } catch (\Throwable $e) {
+                $checks[] = ['Database reachable', false, 'Connection failed: '.$e->getMessage()];
+            }
+        }
+
         $rows    = [];
         $allPass = true;
         foreach ($checks as [$label, $ok, $hint]) {