Add comprehensive code documentation to SecurityCheckTask

- Document all security issue types in the enum
- Document dangerous and high-risk permissions lists
- Add class-level documentation explaining task purpose
- Add detailed KDoc comments for each method explaining:
  * What it checks
  * Parameters
  * Security implications
- Document the SecurityFinding data class
- Add section headers for better code organization

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: davideagostini