feat: add read-only Social Accounts API

Add GET /api/accounts (list with optional ?network= and ?type= filters) and
GET /api/accounts/{socialAccount} (show) endpoints. Include plain-text password
field for AI agent consumption.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

app/Http/Resources/SocialAccountResource.php

@@ -0,0 +1,23 @@
+<?php
+
+namespace App\Http\Resources;
+
+use Illuminate\Http\Request;
+use Illuminate\Http\Resources\Json\JsonResource;
+
+class SocialAccountResource extends JsonResource
+{
+    public function toArray(Request $request): array
+    {
+        return [
+            'id' => $this->id,
+            'network' => $this->network,
+            'username' => $this->username,
+            'email' => $this->email,
+            'password' => $this->password,
+            'type' => $this->type,
+            'created_at' => $this->created_at,
+            'updated_at' => $this->updated_at,
+        ];
+    }
+}