docs: enhance sliding window intuition guide with visual diagrams

Improve intuition.md with practical visualizations and examples:
- Add ASCII flowcharts for Maximize and Minimize window modes
  with color-coded R (Explorer) and L (Gatekeeper) movements
- Convert "Visualizing the Dance" to structured table format
  with Step, R, State, L move, Window, and Result columns
- Add concept-to-code comments linking Explorer/Gatekeeper
  roles to for-loop and while-loop in template
- Add Fixed Window (K=3) example trace after Shape 3
  demonstrating constant-size sliding behavior

Author: lufftw