Add note analysis for key elements and multi-topic split suggestions

[AliBenrami]

Summary

Implement automatic analysis of note content to detect important academic elements and identify multi-topic notes.

SDR Mapping

• 3.1.3 Note Analysis
  • Detect definitions, formulas, and important elements.
  • Visually highlight important content.
  • Detect notes containing multiple topics.
  • Suggest splitting multi-topic notes.

Scope

• Analysis pipeline for note content classification.
• Highlighting model in note UI for detected elements.
• Multi-topic detection with actionable split suggestions.
• Non-destructive suggestion flow (user confirms before split).

Acceptance Criteria

• Definitions/formulas are automatically detected in representative notes.
• Detected items are visibly highlighted in the UI.
• Multi-topic notes trigger split suggestions.
• Users can accept/reject split suggestions without data loss.