fix: register plaintext hljs language and handle profile fetch error

- Register highlight.js plaintext language to fix "Unknown language" error
- Add try/catch around getMyProfile() to handle network errors gracefully
- Add components.d.ts to .gitignore (auto-generated by unplugin-vue-components)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitignore

@@ -11,6 +11,7 @@ node_modules
 dist
 dist-ssr
 *.local
+components.d.ts
 
 # Editor directories and files
 .vscode/*