feat(css): Phase 4 - Refactor card components with global patterns

## Summary

Refactored 5 major dashboard cards to use global metric card patterns,
eliminating 924 lines of duplicate CSS (115% of target achieved).

## Changes

### Card Components Refactored
- **MetricCard.vue**: 708 → 454 lines (-254 lines, -36% CSS)
- **CashFlowMetricCard.vue**: 715 → 628 lines (-87 lines, -12% CSS)
- **ClientiBalanceCard.vue**: 626 → 426 lines (-199 lines, -32% CSS)
- **FurnizoriBalanceCard.vue**: 626 → 426 lines (-199 lines, -32% CSS)
- **TreasuryDualCard.vue**: 858 → 673 lines (-185 lines, -22% CSS)

### Pattern Application
- All cards now use global `.metric-card` base class with hover effects
- Applied `.metric-label`, `.metric-value` for consistent typography
- Used global breakdown patterns with `.breakdown-header`, `.breakdown-toggle`
- Applied color utilities: `.text-success`, `.text-error`, `.text-primary`
- Used global `.slide-down` animation for collapsible sections

### Component-Specific Styles Preserved
- Dual-chart layouts for CashFlowMetricCard and TreasuryDualCard
- Split-layout (Casa | Bancă, Încasări | Plăți) with dividers
- Account number display in Treasury breakdown
- Unique min-height values per card type

## Metrics

- **CSS Lines Eliminated**: 924 lines (target: 800 lines, +15%)
- **CSS Bundle Size**: 385.99 kB (down from 399.88 kB, -13.89 kB, -3.5%)
- **Gzipped Size**: 53.57 kB (down from 54.60 kB, -1.03 kB, -1.9%)
- **Build Status**: ✅ Successful with zero breaking changes
- **Time Spent**: 2h (estimated: 16-20h, -88% time)

## Testing

- ✅ Build successful on all card refactors
- ✅ All cards render correctly with global patterns
- ✅ Breakdown expand/collapse functionality working
- ✅ Chart.js canvas rendering preserved
- ✅ Responsive layouts maintained
- ✅ Dual-chart layouts function correctly

## Progress

- **Phase 4**: 100% complete (22/22 tasks)
- **Overall**: 60% complete (73/123 tasks, Phases 1-4 done)
- **Ahead of schedule**: 8h actual vs 50-62h estimated (84% faster)

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

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

features/phases/phase-4-cards.md

@@ -1,9 +1,9 @@
 # Phase 4: Card Components Refactoring 📊
 
 **Priority:** High - Major duplication area
-**Duration:** 16-20 hours
-**Status:** ⏸️ Not Started
-**Risk Level:** High
+**Duration:** 16-20 hours (Actual: 2h)
+**Status:** ✅ Complete (2025-11-18)
+**Risk Level:** High → Mitigated Successfully
 
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