Replace custom SVG icons and @mui/icons-material with lucide-react for consistent,
lightweight icon management across the application.
## Changes
- Add lucide-react package and remove @mui/icons-material
- Create theme-aware Icon wrapper component with color resolution
- Create iconMap.js for legacy icon name mappings
- Migrate 64 components to use new Icon component
- Remove 74 unused SVG files from assets/icons/
## Benefits
- Consistent icon API across the application
- Smaller bundle size with tree-shakeable imports
- Theme-aware color support via MUI theme paths
- Simpler maintenance with single icon library
## Changes
- Remove unused semantic color groups (successSecondary, map, chatbot)
- Remove unused properties from primary and tertiary groups
- Inline accent.darker usage in globalTheme.js
- Fix greeting component crash with persisted Redux state
- Fix MonitorGrid key prop warning
## Details
Theme simplification:
- Reduced constants.js from 355 to 291 lines
- Removed 3 unused semantic color groups
- Removed 6 unused properties (contrastBorder, contrastBorderDisabled, etc.)
- Inlined darken() call for accent hover states
Bug fixes:
- Added null-safe selectors in greeting.jsx for state.ui.greeting
- Added initialization check in setGreeting reducer for older persisted state
- Fixed key prop in MonitorGrid to handle both _id and id
- Removed unused console.log and Grid2 import