Research Mode & Citations

✨ New Features

• Research Mode: Added optional research-backed blog generation.
• Sources Panel: Added a Sources panel in the editor.
• Inline Citations: Added citation support for researched drafts.
• Generation Phases: Added clearer backend states for research, planning, writing, polishing, and images.

🛠 Fixes

• Citation Display: Fixed researched sources and citations not showing correctly.
• Generation Reliability: Improved failed-generation handling and fallback polling.