Implement Dashboard consolidation + Performance logging

Features:
- Add unified "Dashboard Complet" sheet (Excel) with all 9 sections
- Add unified "Dashboard Complet" page (PDF) with key metrics
- Fix VALOARE_ANTERIOARA NULL bug (use sumar_executiv_yoy directly)
- Add PerformanceLogger class for timing analysis
- Remove redundant consolidated sheets (keep only Dashboard Complet)

Bug fixes:
- Fix Excel formula error (=== interpreted as formula, changed to >>>)
- Fix args.output → args.output_dir in perf.summary()

Performance analysis:
- Add PERFORMANCE_ANALYSIS.md with detailed breakdown
- SQL queries take 94% of runtime (31 min), Excel/PDF only 1%
- Identified slow queries for optimization

Documentation:
- Update CLAUDE.md with new structure
- Add context handover for query optimization task

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

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

.claude/commands/plan-handover.md

@@ -0,0 +1,4 @@
+Save the detailed implementation plan to a markdown file for context handover to another session, then stop.
+
+1. **Save the implementation plan** you created earlier in this session to a markdown file in the project root
+2. **Stop execution** - do not commit anything, just prepare the context for handover to another session