chore(config): update speaches config and ignore sveltekit dashboard

- Simplified .env.example to use localhost SPEACHES_URL
- Removed unused prod_url from SpeachesSettings config
- Added dashboard node_modules and build dirs to .gitignore
- Streamlines local development setup

.gitignore

@@ -36,3 +36,8 @@ Thumbs.db
 .coverage
 htmlcov/
 .pytest_cache/
+
+# Dashboard (SvelteKit)
+dashboard/node_modules/
+dashboard/.svelte-kit/
+dashboard/build/