Safe YAML parsing utilities

[niteshpurohit]

Type: Task
Parent Issue: #430

Summary

Enhanced YAML parsing with safety checks, symbol key conversion, and deep merge capabilities

Scope

Enhanced YAML parsing with safety checks, symbol key conversion, and deep merge capabilities

Not In Scope

• YAML generation
• Custom YAML tags

Acceptance Criteria

• YAML.safe_load includes safety checks
• Symbol key conversion option
• Deep merge support
• Tests verify enhanced parsing
• Documentation with security notes

C++ Native Library: No