fix(frontend): Add comprehensive debug logging for Epic creation

Add detailed console logging to diagnose Epic creation issue where
no request is being sent to backend.

Changes:
- Add form submission event logging in epic-form.tsx
- Add API request/response logging in epicsApi.create
- Add HTTP client interceptor logging for all requests/responses
- Log authentication status, payload, and error details
- Log form validation state and errors

This will help identify:
- Whether form submit event fires
- Whether validation passes
- Whether API call is triggered
- Whether authentication token exists
- What errors occur (if any)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

lib/api/pm.ts

@@ -26,7 +26,15 @@ export const epicsApi = {
   },
 
   create: async (data: CreateEpicDto): Promise<Epic> => {
-    return api.post('/api/v1/epics', data);
+    console.log('[epicsApi.create] Sending request', { url: '/api/v1/epics', data });
+    try {
+      const result = await api.post('/api/v1/epics', data);
+      console.log('[epicsApi.create] Request successful', result);
+      return result;
+    } catch (error) {
+      console.error('[epicsApi.create] Request failed', error);
+      throw error;
+    }
   },
 
   update: async (id: string, data: UpdateEpicDto): Promise<Epic> => {