feat: ability and integration infrastructure

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

src/Integrations/Integration.php

@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+namespace LIT\MCP\Integrations;
+
+use LIT\MCP\Abilities\Ability;
+
+/**
+ * A group of abilities that is only registered when its theme/plugin is active.
+ */
+interface Integration
+{
+    public function id(): string;
+
+    public function isAvailable(): bool;
+
+    /** @return list<Ability> */
+    public function abilities(): array;
+}

src/Integrations/IntegrationRegistry.php

@@ -0,0 +1,51 @@
+<?php
+
+declare(strict_types=1);
+
+namespace LIT\MCP\Integrations;
+
+use LIT\MCP\Abilities\Ability;
+
+final class IntegrationRegistry
+{
+    /** @var list<Integration> */
+    private array $integrations;
+
+    public function __construct(Integration ...$integrations)
+    {
+        $this->integrations = array_values($integrations);
+    }
+
+    /** @return list<Integration> */
+    public function available(): array
+    {
+        return array_values(array_filter(
+            $this->integrations,
+            static fn (Integration $integration): bool => $integration->isAvailable()
+        ));
+    }
+
+    /** @return list<Ability> */
+    public function abilities(): array
+    {
+        $abilities = [];
+        foreach ($this->available() as $integration) {
+            array_push($abilities, ...$integration->abilities());
+        }
+
+        return $abilities;
+    }
+
+    /** @return list<string> */
+    public function directAbilityNames(): array
+    {
+        $names = [];
+        foreach ($this->abilities() as $ability) {
+            if ($ability->isDirect()) {
+                $names[] = $ability->name();
+            }
+        }
+
+        return $names;
+    }
+}