feat: Improve trial balance display and PDF export with class totals

- Change totals display to single horizontal line using shared CSS
- Rename column headers from "Sold Prec" to "Sume Prec" (correct terminology)
- Add class totals (TOTAL CLASA 1-7) and grand total to PDF export
- Style class totals with light gray background, grand total with darker gray
- Update CLAUDE.md with rule to use shared CSS instead of creating new styles

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

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

CLAUDE.md

@@ -186,8 +186,11 @@ ttl_your_data: int = int(os.getenv('CACHE_TTL_YOUR_DATA', '600'))  # 10 min defa
 **Golden Rules**:
 - ✅ Use global patterns first (`.roa-card`, `.roa-metric`, `.roa-badge-*`) - check `CSS_PATTERNS.md`
 - ✅ Use design tokens (`var(--color-primary)`) not hardcoded values (`#2563eb`)
+- ✅ **Use shared CSS** from `src/assets/css/` - NEVER create new CSS when shared classes exist
+- ✅ For inline stats/totals use `.summary-stats-inline`, `.stat-item`, `.stat-label`, `.stat-value` from `stats.css`
 - ❌ Never use `:deep()` in components (use `src/assets/css/vendor/` for PrimeVue overrides)
 - ❌ Never duplicate CSS (write once, use everywhere)
+- ❌ Never add new scoped CSS for patterns that already exist in shared CSS files
 
 **Tables - Unified Column Structure & Filter Buttons**:
 - ✅ **ALWAYS use separate columns** for related data (Debit | Credit, not Debit+Credit stacked)