Enhance welcome module with embed text rendering and autorole management

- Updated the welcome embed functionality to allow for user mentions in titles, authors, and footers, while maintaining clickable mentions in descriptions.
- Implemented autorole assignment logic with checks for role manageability and hierarchy, including detailed logging for skipped roles.
- Improved the WebUI to display real user and guild data in the welcome embed preview, enhancing user experience.
- Refactored the welcome text rendering to support additional options for mention handling based on the context of the embed fields.

packages/shared/src/phase2.test.ts

@@ -27,6 +27,17 @@ describe('phase2 helpers', () => {
     expect(result).toBe('Join <#123456789012345678> please');
   });
 
+  it('maps embed text fields with field names', async () => {
+    const { mapEmbedTextFields } = await import('./phase2.js');
+    const mapped = mapEmbedTextFields(
+      { title: 'T:{user}', description: 'D:{user}', footerText: 'F:{user}' },
+      (value, field) => `${field}:${value}`
+    );
+    expect(mapped.title).toBe('title:T:{user}');
+    expect(mapped.description).toBe('description:D:{user}');
+    expect(mapped.footerText).toBe('footerText:F:{user}');
+  });
+
   it('accepts extended embed fields', async () => {
     const { WelcomeEmbedSchema, embedHasContent } = await import('./phase2.js');
     const parsed = WelcomeEmbedSchema.parse({