feat(usernames): update unique constraint to composite with type and provider

- Remove single unique constraint on username
  - Add composite unique constraint on username, username_type, and provider_type
  - Update Filament username form validation with custom unique rule
  - Add descriptive validation message for duplicate usernames

app/Filament/Resources/Usernames/Schemas/UsernameForm.php

@@ -9,7 +9,9 @@ use Filament\Forms\Components\Select;
 use Filament\Forms\Components\TextInput;
 use Filament\Forms\Components\ToggleButtons;
 use Filament\Infolists\Components\TextEntry;
+use Filament\Schemas\Components\Utilities\Get;
 use Filament\Schemas\Schema;
+use Illuminate\Validation\Rules\Unique;
 
 class UsernameForm
 {
@@ -21,7 +23,19 @@ class UsernameForm
                     ->columnSpan(1)
                     ->alphaDash()
                     ->helperText('Email: myusername@gmail.com | Username: myusername')
-                    ->required(),
+                    ->required()
+                    ->unique(
+                        table: 'usernames',
+                        ignoreRecord: true,
+                        modifyRuleUsing: function (Unique $rule, Get $get) {
+                            return $rule
+                                ->where('username_type', $get('username_type'))
+                                ->where('provider_type', $get('provider_type'));
+                        },
+                    )
+                    ->validationMessages([
+                        'unique' => 'The username already exists for this type and provider.',
+                    ]),
                 TextInput::make('daily_mailbox_limit')
                     ->integer()
                     ->minValue(1)

database/migrations/2025_12_09_180756_update_usernames_unique_constraint_remove_single_add_composite.php

@@ -0,0 +1,37 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        Schema::table('usernames', function (Blueprint $table) {
+            // Drop the existing unique constraint on 'username' column
+            $table->dropUnique('usernames_username_unique');
+
+            // Add a composite unique constraint on username, username_type, and provider_type
+            // This allows the same username with different type combinations
+            $table->unique(['username', 'username_type', 'provider_type'], 'usernames_username_type_provider_unique');
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::table('usernames', function (Blueprint $table) {
+            // Drop the composite unique constraint
+            $table->dropUnique('usernames_username_type_provider_unique');
+
+            // Restore the original single unique constraint on 'username'
+            $table->unique('username', 'usernames_username_unique');
+        });
+    }
+};