feat: Add WYSIWYG editor components and utilities

- Implemented WysiwygModalManager for managing modals related to code blocks and block settings.
- Created WysiwygSelection for handling text selection across Shadow DOM boundaries.
- Introduced WysiwygShortcuts for managing keyboard shortcuts and slash menu items.
- Developed wysiwygStyles for consistent styling of the WYSIWYG editor.
- Defined types for blocks, slash menu items, and shortcut patterns in wysiwyg.types.ts.

ts_web/elements/dees-input-wysiwyg/blocks/block.registry.ts

@@ -0,0 +1,17 @@
+import type { IBlockHandler } from './block.base.js';
+
+export class BlockRegistry {
+  private static handlers = new Map<string, IBlockHandler>();
+  
+  static register(type: string, handler: IBlockHandler): void {
+    this.handlers.set(type, handler);
+  }
+  
+  static getHandler(type: string): IBlockHandler | undefined {
+    return this.handlers.get(type);
+  }
+  
+  static getAllTypes(): string[] {
+    return Array.from(this.handlers.keys());
+  }
+}