Add caching layer with SQLite backend

[AdmGenSameer]

• Implement SQLite-based caching with 24h TTL
• Add --no-cache flag to bypass cache
• Add --cache-stats and --clear-cache commands
• Integrate caching into all search functions (AUR, pacman, APT, DNF, Flatpak, Snap)
• Privacy-conscious design filters sensitive queries
• Cache stored in user config directory (~/.cache/archpkg-helper/)
• Significant performance improvements for repeated searches

Fixes: Search performance optimization
Features: Caching layer, cache management commands

Description

Related Issue

Fixes #<issue_number>

Changes Made

• Updated ...
• Added ...
• Removed ...

Screenshots or GIFs (if applicable)

Checklist

• Code is formatted with the project’s Prettier config provided in .prettierrc (if present).
• Only the necessary files are modified; no unrelated changes are included.
• Follows clean code principles (readable, maintainable, minimal duplication).
• All changes are clearly documented.
• Code has been tested (manual/automated) and verified against edge cases.
• No breaking changes are introduced to existing functionality.
• All new and existing tests passed (if tests exist).

Additional Notes

Fixes #64