Features:
- Add meter display modes (Bar/Text/Graph/Hidden) accessible via F2 Setup
- Add CPU user/system breakdown in bars (green=user, red=system)
- Add htop-style braille graph rendering with paired sample encoding
- Add column visibility configuration in F2 Setup menu
- Add history buffers for CPU/memory graph modes (512 samples)

Fixes:
- Fix show_kernel_threads, show_user_threads settings (now filter properly)
- Fix show_program_path toggle (switches between full path and name)
- Remove unused code: toggle_tree_collapse, find_prev, kill_selected methods
- Remove unused fields: previous_pids, new_pids, dying_pids, highlight_time

Technical:
- Use NtQuerySystemInformation for per-core CPU breakdown
- Update to Rust 2024 edition
- Dynamic column rendering based on visibility config

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>