feat: enhance project creation wizard with folder creation and git clone progress

- Add "+" button to create new folders directly from folder browser
- Add SSE endpoint for git clone with real-time progress display
- Show clone progress (receiving objects, resolving deltas) in UI
- Detect SSH URLs and display "SSH Key" instead of "No authentication"
- Hide token section for SSH URLs (tokens only work with HTTPS)
- Fix auto-advance behavior: only auto-advance for "Existing Workspace"
- Fix various misleading UI messages
- Support auth token via query param for SSE endpoints

src/utils/api.js

@@ -158,6 +158,12 @@ export const api = {
     return authenticatedFetch(`/api/browse-filesystem?${params}`);
   },
 
+  createFolder: (folderPath) =>
+    authenticatedFetch('/api/create-folder', {
+      method: 'POST',
+      body: JSON.stringify({ path: folderPath }),
+    }),
+
   // User endpoints
   user: {
     gitConfig: () => authenticatedFetch('/api/user/git-config'),