Improves event layout and stacking logic

Refactors the event layout and stacking logic based on review feedback.

This includes:
- Merging conflicting event groups to prevent inconsistencies.
- Implementing minimal stack level assignment using a min-heap.
- Consolidating styling and using DateService for drag operations.
- Adding reflow after drag and drop.
- Improving the column event filtering to include events overlapping midnight.
- Ensuring explicit sorting of events for grid layout.

docs/cyclomatic-complexity-report.md

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+# Cyclomatic Complexity Analysis Report
+## Calendar Plantempus TypeScript Codebase
+
+**Generated:** 2025-10-06  
+**Analyzer:** Roo AI Assistant  
+**Total Files Analyzed:** 40+
+
+---
+
+## Executive Summary
+
+### Complexity Distribution
+
+| Complexity Range | Risk Level | Count | Percentage |
+|-----------------|------------|-------|------------|
+| 1-10 | ✅ Low | TBD | TBD% |
+| 11-20 | ⚠️ Medium | TBD | TBD% |
+| 21-50 | 🔴 High | TBD | TBD% |
+| 50+ | 💀 Critical | TBD | TBD% |
+
+### Key Metrics
+- **Total Functions:** TBD
+- **Average Complexity:** TBD
+- **Highest Complexity:** TBD
+- **Files Needing Refactoring:** TBD
+
+---
+
+## Methodology
+
+### Cyclomatic Complexity Calculation
+For each function, we count:
+- **+1** for the function itself
+- **+1** for each `if`, `else if`, `while`, `for`, `case`
+- **+1** for each `&&`, `||` in conditions
+- **+1** for each `catch` block
+- **+1** for each ternary operator `? :`
+- **+1** for each `return` statement (except the last one)
+
+### Risk Assessment
+- **1-10:** Simple, easy to test and maintain
+- **11-20:** Moderate complexity, acceptable
+- **21-50:** Complex, should be refactored
+- **50+:** Very complex, high maintenance risk
+
+---
+
+## Analysis in Progress...
+
+This report is being generated. Please wait for the complete analysis.