feat: Add PWA support and consolidate CSS design system

- Add PWA manifest, icons (192x192, 512x512), and service worker
- Register service worker in index.html with Apple mobile web app support
- Consolidate CSS variables and design tokens documentation
- Update PrimeVue overrides for consistent theming
- Refactor data-entry components to use shared CSS patterns
- Add frontend-style-auditor agent for style consistency checks
- Minor OCR validation and job worker improvements
- Update start-prod.sh configuration

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/assets/css/components/stats.css

@@ -278,7 +278,7 @@
 
 /* Heat Map Colors for Mini Cards */
 .mini-stat-card.heat-low {
-  background: #f0fdf4;
+  background: var(--green-50);
   border-color: var(--color-success);
 }
 
@@ -287,7 +287,7 @@
 }
 
 .mini-stat-card.heat-medium {
-  background: #fffbeb;
+  background: var(--yellow-50);
   border-color: var(--color-warning);
 }
 
@@ -296,7 +296,7 @@
 }
 
 .mini-stat-card.heat-high {
-  background: #fef2f2;
+  background: var(--red-50);
   border-color: var(--color-error);
 }
 
@@ -332,30 +332,30 @@
 
 /* Stats Card Variants */
 .stats-card.clients {
-  border-left-color: #3b82f6;
+  border-left-color: var(--blue-500);
 }
 
 .stats-card.clients .stats-card-header i {
-  color: #3b82f6;
-  background: #eff6ff;
+  color: var(--blue-500);
+  background: var(--blue-50);
 }
 
 .stats-card.suppliers {
-  border-left-color: #f59e0b;
+  border-left-color: var(--yellow-500);
 }
 
 .stats-card.suppliers .stats-card-header i {
-  color: #f59e0b;
-  background: #fffbeb;
+  color: var(--yellow-600);
+  background: var(--yellow-50);
 }
 
 .stats-card.treasury {
-  border-left-color: #10b981;
+  border-left-color: var(--green-500);
 }
 
 .stats-card.treasury .stats-card-header i {
-  color: #10b981;
-  background: #ecfdf5;
+  color: var(--green-500);
+  background: var(--green-50);
 }
 
 /* Responsive Adjustments */