**Motivations:**
- Better error handling when endpoints return HTML error pages instead of JSON
- Provide clearer error messages to users
**Root causes:**
- Some NIP-95 endpoints (e.g., nostrimg.com) return HTML error pages instead of JSON
- Current error handling only catches JSON parse errors without detecting HTML responses
- Users get confusing error messages about JSON parsing when the real issue is an HTML response
**Correctifs:**
- Added HTML detection before JSON parsing
- Extract error message from HTML title or h1 tags when possible
- Provide clearer error message indicating HTML response instead of JSON
- Improved error logging with HTML body preview
**Evolutions:**
- None
**Pages affectées:**
- pages/api/nip95-upload.ts