fix: close etappe-0 whole-branch review findings

- Autoloader: add automattic/jetpack-autoloader and load
  vendor/autoload_packages.php; require wordpress/mcp-adapter directly (^0.5).
- ServerRegistrar: make the adapter create_server() call and the
  OAuthServerRegistrar class_exists() check injectable so createServer()'s
  unhook-before-create ordering and the "mcp-oauth absent" branch are unit
  tested; add a smoke-test check that booting REST triggers no
  _doing_it_wrong().
- mcp-smoke.sh: assert mcp-adapter's default server route 404s, and that the
  subscriber role-gate denial actually carries our/the adapter's denial text
  (not just any isError/error).
- Guard tests/Integration/mint-token.php and tec-probe.php with
  `defined('WP_CLI') && WP_CLI || exit;`; add .gitattributes export-ignore
  for tests/docs-superpowers/.superpowers/phpunit/phpcs config.
- Security: add Server/RequestContext, tracking via
  rest_request_before_callbacks whether the current REST dispatch is our
  OAuth-protected /mcp/mcp-oauth-server route; AbilityRegistrar's
  permission_callback now denies (after the role gate) when abilities are
  invoked outside that route. Wired in Plugin::boot().
- Minors: single Plugin::VERSION constant used by ServerRegistrar;
  IntegrationRegistry caches its computed abilities list; tec-probe.php
  checks wp_insert_post's result and cleans up its probe post in a
  try/finally.

composer test: 47/47 green. composer lint: clean. Full mcp-smoke.sh run ends
ALL CHECKS PASSED (plus the expected /.well-known WARN).

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01At3V6SjwbMe6eMzVGW3Hs7

tests/Unit/Server/ServerRegistrarTest.php

@@ -146,4 +146,69 @@ final class ServerRegistrarTest extends TestCase
 
         (new ServerRegistrar($this->registry(), $this->instructions()))->unhookOAuthDefaultServer();
     }
+
+    public function testUnhookOAuthDefaultServerIsNoOpWhenOAuthPackageIsAbsent(): void
+    {
+        $oauthRegistrar = Mockery::mock(OAuthServerRegistrar::class);
+        $oauthCallback = [$oauthRegistrar, 'register_server'];
+        $hook = new class {
+            /** @var array<int, array<string, array{function: mixed, accepted_args: int}>> */
+            public array $callbacks = [];
+        };
+        $hook->callbacks = [10 => ['oauth-id' => ['function' => $oauthCallback, 'accepted_args' => 0]]];
+        $GLOBALS['wp_filter']['mcp_adapter_init'] = $hook;
+
+        Functions\expect('remove_action')->never();
+
+        // Simulate wp-media/mcp-oauth not being installed via the injectable
+        // classExists probe (class_exists() is a PHP internal and cannot be
+        // stubbed directly through Brain\Monkey/Patchwork).
+        $registrar = new ServerRegistrar(
+            $this->registry(),
+            $this->instructions(),
+            null,
+            null,
+            static fn (): bool => false
+        );
+
+        $registrar->unhookOAuthDefaultServer();
+    }
+
+    public function testCreateServerUnhooksOAuthDefaultServerBeforeCreatingAdapterServer(): void
+    {
+        Functions\when('doing_action')->justReturn(true);
+        Functions\when('is_wp_error')->justReturn(false);
+
+        $oauthRegistrar = Mockery::mock(OAuthServerRegistrar::class);
+        $oauthCallback = [$oauthRegistrar, 'register_server'];
+        $hook = new class {
+            /** @var array<int, array<string, array{function: mixed, accepted_args: int}>> */
+            public array $callbacks = [];
+        };
+        $hook->callbacks = [10 => ['oauth-id' => ['function' => $oauthCallback, 'accepted_args' => 0]]];
+        $GLOBALS['wp_filter']['mcp_adapter_init'] = $hook;
+
+        /** @var list<string> $order */
+        $order = [];
+        Functions\expect('remove_action')
+            ->once()
+            ->with('mcp_adapter_init', $oauthCallback, 10)
+            ->andReturnUsing(static function () use (&$order): void {
+                $order[] = 'unhook';
+            });
+
+        $registrar = new ServerRegistrar(
+            $this->registry(),
+            $this->instructions(),
+            static fn (): bool => true,
+            static function (array $args) use (&$order): bool {
+                $order[] = 'create';
+                return true;
+            }
+        );
+
+        $registrar->createServer();
+
+        self::assertSame(['unhook', 'create'], $order, 'unhook must run before the adapter creates the server');
+    }
 }