feat: implement cost report template generator with Claude session tracking (issue #119)

Comprehensive cost tracking system implementation including:

- Cost report generator with multiple formats (summary, detailed, audit)
- Full CLI integration with cost management commands
- Claude session cost tracking and estimation
- Professional markdown reports with frontmatter/contentmatter
- Automatic cost note generation for issue implementations
- Complete test coverage (33 test cases)
- Database integration with finance schema initialization

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

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

markitect/finance/__init__.py

@@ -0,0 +1,31 @@
+"""
+Finance module for MarkiTect cost tracking system.
+
+This module provides comprehensive financial management capabilities including:
+- Cost item management (monthly recurring and one-time costs)
+- Period-based cost allocation to active issues
+- Financial reporting and audit trails
+- Integration with issue management system
+
+Core Components:
+- models: Database models and schema definitions
+- cost_manager: Cost item lifecycle management
+- period_manager: Calculation period management
+- allocation_engine: Cost distribution algorithms
+- reports: Financial reporting and analytics
+"""
+
+from .models import FinanceModels
+from .cost_manager import CostItemManager, CostItem, CostCategory
+from .report_generator import CostReportGenerator, ReportConfig
+from .cli import cost_commands
+
+__all__ = [
+    'FinanceModels',
+    'CostItemManager',
+    'CostItem',
+    'CostCategory',
+    'CostReportGenerator',
+    'ReportConfig',
+    'cost_commands'
+]