refactor(skills): Phase 2.3 - Extract ui5-integration-cards references

Extracted 3 largest sections to progressive disclosure references:

1. data-configuration-patterns.md (156 lines)
   - Primary data location rules
   - Inline JSON, network requests, destinations
   - Path overriding patterns
   - Parameter binding
   - Extension data sources

2. card-types-examples.md (111 lines)
   - Complete examples for all 6 card types
   - List, Table, Calendar, Timeline, Object
   - Manifest structure for each type

3. analytical-cards-comprehensive.md (227 lines)
   - 43+ chart types with feed UIDs
   - Measures, dimensions, feeds configuration
   - Advanced chart properties
   - VizProperties customization

Main skill file:
- Before: 805 lines
- After: 489 lines
- Reduction: -316 lines (-39%)

All sections replaced with essential patterns and quick references.

Phase 2 Complete:
- ui5-best-practices: -23% (862 → 663)
- ui5-typescript-expert: -44% (929 → 517)
- ui5-integration-cards: -39% (805 → 489)

Total context reduction: -1,339 lines (-35%)

Tests: ✅ All structure tests passing

Author: d3xter666