[LifetimeSafety] Refactor the analysis into smaller files

[usx95]

TL;DR

Restructure the C++ Lifetime Safety Analysis into a modular, component-based architecture with clear separation of concerns.

What changed?

This PR reorganizes the C++ Lifetime Safety Analysis code by:

1. Breaking up the monolithic LifetimeSafety.cpp (1500+ lines) into multiple smaller, focused files
2. Creating a dedicated LifetimeSafety directory with a clean component structure
3. Introducing header files for each component with proper documentation
4. Moving existing code into the appropriate component files:
   • Checker.h/cpp: Core lifetime checking logic
   • Dataflow.h: Generic dataflow analysis framework
   • Facts.h: Lifetime-relevant events and fact management
   • FactsGenerator.h/cpp: AST traversal for fact generation
   • LiveOrigins.h/cpp: Backward dataflow analysis for origin liveness
   • LoanPropagation.h/cpp: Forward dataflow analysis for loan tracking
   • Loans.h: Loan and access path definitions
   • Origins.h: Origin management
   • Reporter.h: Interface for reporting lifetime violations
   • Utils.h: Common utilities for the analysis

The code functionality remains the same, but is now better organized with clearer interfaces between components.

Why make this change?

This restructuring improves maintainability and extensibility of the lifetime safety analysis by:

1. Making the code more modular and easier to understand
2. Providing clear separation between different analysis components
3. Establishing well-defined interfaces between components
4. Making it easier to extend or modify individual parts of the analysis
5. Improving documentation with dedicated header files for each component
6. Preparing the codebase for future enhancements to the lifetime safety model

[usx95]

• [LifetimeSafety] Refactor the analysis into smaller files #162474 👈 (View in Graphite)
• main

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[github-actions]

✅ With the latest revision this PR passed the C/C++ code formatter.