feat: ServiceDefinition for Chain and Names modules

ChainService (code=chain, no deps) and NamesService (code=names,
depends on chain). Ready for CorePHP service registry discovery
when core-api package is installed.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/Mod/Chain/ChainService.php

@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Mod\Chain;
+
+/**
+ * Chain service definition for the CorePHP service registry.
+ *
+ *   $service = ChainService::definition();
+ *   echo $service['code']; // 'chain'
+ */
+class ChainService
+{
+    public static function definition(): array
+    {
+        return [
+            'code' => 'chain',
+            'module' => 'Mod\\Chain',
+            'name' => 'Blockchain',
+            'tagline' => 'Lethean blockchain daemon and wallet RPC',
+            'description' => 'Core chain infrastructure — daemon, wallet, alias management, PoW+PoS consensus.',
+            'icon' => 'link',
+            'color' => '#34d399',
+            'sort_order' => 10,
+        ];
+    }
+
+    public static function version(): string
+    {
+        return '1.0.0';
+    }
+
+    public static function dependencies(): array
+    {
+        return [];
+    }
+}

app/Mod/Names/NamesService.php

@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Mod\Names;
+
+/**
+ * Names service definition for the CorePHP service registry.
+ *
+ *   $service = NamesService::definition();
+ *   echo $service['code']; // 'names'
+ */
+class NamesService
+{
+    public static function definition(): array
+    {
+        return [
+            'code' => 'names',
+            'module' => 'Mod\\Names',
+            'name' => '.lthn Registrar',
+            'tagline' => 'Blockchain domain name registration and DNS management',
+            'description' => 'Register .lthn names on-chain, manage DNS records via ITNS sidechain, sunrise period claims.',
+            'icon' => 'globe',
+            'color' => '#818cf8',
+            'sort_order' => 20,
+        ];
+    }
+
+    public static function version(): string
+    {
+        return '1.0.0';
+    }
+
+    public static function dependencies(): array
+    {
+        return ['chain'];
+    }
+}