load template workflow via URL query param (#6546)

## Summary

Adds support for loading templates via URL query parameters. Users can
now share direct links to templates.

To test:

1. checkout this branch
2. start dev server on port 5173
3. go to http://localhost:5173/?template=image_qwen_image_edit_2509

**Examples:**
- `/?template=default` - Loads template with default source
- `/?template=flux_simple&source=custom` - Loads from custom source

Includes error handling with toast notifications for invalid templates
and comprehensive test coverage.

---------

Co-authored-by: Christian Byrne <c.byrne@comfy.org>

pnpm-lock.yaml

@@ -12,15 +12,9 @@ catalogs:
     '@eslint/js':
       specifier: ^9.35.0
       version: 9.35.0
-    '@iconify-json/lucide':
-      specifier: ^1.1.178
-      version: 1.2.66
     '@iconify/json':
       specifier: ^2.2.380
       version: 2.2.380
-    '@iconify/tailwind':
-      specifier: ^1.1.3
-      version: 1.2.0
     '@intlify/eslint-plugin-vue-i18n':
       specifier: ^4.1.0
       version: 4.1.0