chore: clean up dotfiles and add gitignore whitelist

Switch to whitelist-based .gitignore to only track essential configs:
nvim, yazi, kitty, zsh, ideavim, karabiner, tmux, scripts, starship.
Remove history, compiled files, and plugin dirs from tracking.

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

.gitignore

@@ -0,0 +1,58 @@
+# Ignore everything by default
+*
+!.gitignore
+
+# === Core dotfiles ===
+
+# Neovim
+!nvim/
+!nvim/**
+nvim/plugin/
+nvim/.nvimlog
+nvim/lazy-lock.json
+
+# Yazi
+!yazi/
+!yazi/**
+yazi/plugins/
+
+# Kitty
+!kitty/
+!kitty/**
+
+# Zsh (only .zshrc)
+!zsh/
+!zsh/.zshrc
+
+# IdeaVim
+!ideavim/
+!ideavim/**
+
+# === Definitely persist ===
+
+# Karabiner (not automatic_backups)
+!karabiner/
+!karabiner/**
+karabiner/automatic_backups/
+
+# Tmux (not plugins)
+!tmux/
+!tmux/**
+tmux/plugins/
+
+# Scripts
+!scripts/
+!scripts/**
+
+# Starship prompt
+!starship.toml
+
+# === Always ignore ===
+.DS_Store
+**/.DS_Store
+**/.claude/
+*.nvimlog
+*.log
+*.bak
+kitty/kitty-themes/
+kitty/kitty-dark.png