Add shape prefix to symbol IDs, fix brand naming, add assets

- Symbol IDs now include shape for uniqueness: {shape}_{brand}_{mode}
  e.g., text-only_paypal_lm, rectangle_visa_la, icon_mastercard_dm
- Fixed brand name inconsistencies:
  - amazon_pay → amazon
  - naverpay → naver_pay
  - p24 → przelewy24
  - direct_debit → bacs (unified BACS Direct Debit name)
- Added font assets (FontAwesome, Material Icons)
- Added MprIconsAssets and MprIconsConfig classes
- Updated preview.html with shape parameter support
- All 752 icons complete (38 payment × 4 shapes × 4 modes + 12 social × 3 shapes × 4 modes)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/MprIcons.php

@@ -367,4 +367,25 @@ class MprIcons
     {
         return array_keys(self::$map);
     }
+
+    /**
+     * Register icon font CSS assets
+     * Convenience method that delegates to MprIconsAssets
+     * Call from hookHeader or setMedia
+     *
+     * @param \Module $module The module instance
+     * @return bool Whether assets were registered
+     */
+    public static function registerAssets(\Module $module): bool
+    {
+        return MprIconsAssets::registerAssets($module);
+    }
+
+    /**
+     * Check if self-hosted icon fonts are enabled
+     */
+    public static function isSelfHostEnabled(): bool
+    {
+        return MprIconsConfig::isSelfHostEnabled();
+    }
 }