Add optional Tone field to Sites for AI content generation

- Add tone column to sites table (nullable string)
- Add TONES constant to Site model with predefined options:
  professional, casual, technical, friendly, formal, humorous,
  conversational, authoritative, inspirational, educational, minimal, detailed
- Update Sites Livewire component to edit tone
- Update Sites view with tone select dropdown in form
- Add tone column to sites table display
- Add tone to SiteResource API response

AI agents can now read the site's tone and use it when generating content.

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

database/migrations/2026_07_27_000005_add_tone_to_sites_table.php

@@ -0,0 +1,22 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    public function up(): void
+    {
+        Schema::table('sites', function (Blueprint $table) {
+            $table->string('tone')->nullable()->after('api_instructions');
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::table('sites', function (Blueprint $table) {
+            $table->dropColumn('tone');
+        });
+    }
+};