Feature/optimization attempts - add new image filters and UI improvements

[medeirosdev]

feat: add new image filters and UI improvements

New Features:

• Edge Detection: Sobel X, Sobel Y, Sobel Magnitude
• Noise Reduction: Median Filter with adjustable kernel size
• Color Filters: Grayscale, Sepia, RGB Channel Swap
  Files Added:
• src/utils/edgeDetection.ts - Sobel operator implementation
• src/utils/noiseReduction.ts - Median filter implementation
• src/utils/colorFilters.ts - Color transformation filters
• public/favicon.svg - Custom app icon
  Files Modified:
• types/index.ts - Added 7 new FilterType values
• App.tsx - Integrated new filters in processImageSync
• imageWorker.ts - Added filter processing in Web Worker
• Sidebar.tsx - Added 3 new filter categories, collapsed by default
• FormulaPanel.tsx - Added LaTeX formulas for new filters
• index.html - Updated favicon and page title
  Code Cleanup:
• Removed unused exports and debug statements
• Cleaned convolution.ts kernels
  UI Improvements:
• Sidebar categories start collapsed
• New custom favicon with gradient
• Updated page title