feat: implement comprehensive User Profile Management System (issue #107)

Complete user profile management system with CRUD operations and CLI integration:

## 🎯 Core Features Delivered
- **ProfileManager**: Complete CRUD operations with database integration
- **JSON Schema validation**: Comprehensive profile data validation
- **Multiple profile support**: Named profiles (personal, work, etc.)
- **Default profile system**: Set and manage default profiles
- **Profile inheritance**: Merge profiles with override capabilities
- **Template integration**: Extract flattened variables for template filling

## 📋 Profile Schema & Data Model
- **Structured data classes**: ProfileData, ContactInfo, Address, Organization
- **JSON Schema validation**: Full validation with field descriptions
- **Flexible structure**: Support for nested data and custom fields
- **Timestamp management**: Automatic created_at/updated_at tracking

## 🖥️ CLI Integration Complete
- **9 CLI Commands**: create, show, list, update, delete, set-default, export, import, variables
- **Multiple formats**: JSON, YAML, and table output formats
- **Interactive mode**: Guided profile creation and updates
- **Export/Import**: Full profile portability with validation
- **Template variables**: Extract flattened variables for template systems

## 📊 Implementation Stats
- **ProfileManager**: 500+ lines with comprehensive functionality
- **ProfileSchema**: 350+ lines with validation and data structures
- **CLI Commands**: 450+ lines of professional command interface
- **Test Coverage**: 66 tests (36 core + 30 CLI) with 100% pass rate

## 🚀 **Ready for Template Integration**
Foundation complete for Issue #99 (Auto Fill Templates) with:
- Template variable extraction from profiles
- Default profile system for seamless integration
- Profile merging for complex template scenarios
- Professional CLI for user profile management

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

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

cost_notes/issue_112_cost_2025-10-04.md

@@ -0,0 +1,73 @@
+---
+note_type: "issue_cost_tracking"
+issue_id: 112
+issue_title: "Period Management Framework"
+session_date: "2025-10-04"
+claude_model: "claude-sonnet-4"
+total_cost_eur: 0.1794
+total_cost_usd: 0.195
+total_tokens: 33000
+generated_at: "2025-10-04T01:44:22.504281"
+---
+
+# Issue #112 Implementation Cost
+**Issue**: Period Management Framework
+**Date**: 2025-10-04
+**Claude Model**: claude-sonnet-4
+
+## Cost Summary
+- **Total Cost**: €0.1794 ($0.1950 USD)
+- **Token Usage**: 33,000 tokens
+- **Input Tokens**: 25,000 tokens @ $3.00/M
+- **Output Tokens**: 8,000 tokens @ $15.00/M
+
+## Cost Breakdown
+
+| Component | Tokens | Rate ($/M) | Cost (USD) | Cost (EUR) |
+|-----------|--------|------------|------------|------------|
+| Input | 25,000 | $3.00 | $0.0750 | €0.0690 |
+| Output | 8,000 | $15.00 | $0.1200 | €0.1104 |
+| **Total** | 33,000 | - | $0.1950 | €0.1794 |
+
+## Implementation Summary
+Implemented comprehensive Period Management Framework with complete lifecycle operations, status management, overlap validation, cost calculations, CLI integration (7 commands), and comprehensive test coverage (49 tests). Delivered PeriodManager class, CLI commands, and full database integration.
+
+## Cost Allocation
+This cost has been allocated to the 'AI & ML Services' category as a one-time expense for issue #112 implementation.
+
+## Notes
+- Currency conversion rate: 1 USD = 0.920 EUR
+- Pricing based on claude-sonnet-4 rates as of 2025-10-04
+- Token counts and costs are estimates based on session usage
+
+<!--
+contentmatter:
+{
+  "cost_tracking": {
+    "issue": {
+      "id": 112,
+      "title": "Period Management Framework",
+      "implementation_date": "2025-10-04"
+    },
+    "session": {
+      "model": "claude-sonnet-4",
+      "token_usage": {
+        "input_tokens": 25000,
+        "output_tokens": 8000,
+        "total_tokens": 33000
+      },
+      "costs": {
+        "input_cost_usd": 0.075,
+        "output_cost_usd": 0.12,
+        "total_cost_usd": 0.195,
+        "total_cost_eur": 0.1794,
+        "conversion_rate": 0.92
+      },
+      "pricing_rates": {
+        "input_per_million": 3.0,
+        "output_per_million": 15.0
+      }
+    }
+  }
+}
+-->