feat: migrate from Zsh to Fish shell with comprehensive configuration

Major shell migration replacing Zsh/Oh-My-Zsh with Fish shell:

- Remove all Zsh configurations (dot_zshrc.tmpl, dot_p10k.zsh)
- Remove Oh-My-Zsh external dependencies from .chezmoiexternal.toml
- Add complete Fish shell setup with config.fish.tmpl and abbr.fish.tmpl
- Implement Fish-native functions for lazy-loading tools (mise, pyenv, zoxide, etc.)
- Create commonrc.fish.tmpl for cross-shell compatibility
- Add Fish plugin management via Fisher (tide prompt, fzf.fish)
- Update documentation (CLAUDE.md, TODO.md, ONBOARDING.md) to reflect Fish
- Add .fish.tmpl file association to VS Code settings
- Enhance PowerShell profile with lsd aliases
- Configure git delta pager and zdiff3 merge conflict style
- Update WSL keychain integration for Fish shell

This migration maintains all existing tool integrations while improving
startup performance through lazy-loading and Fish's native features.

home/Documents/PowerShell/Microsoft.PowerShell_profile.ps1.tmpl

@@ -21,10 +21,13 @@ Set-Alias -Name nano -Value micro
 Set-Alias -Name vim -Value nvim
 Set-Alias -Name lg -Value lazygit
 
-# Directory listing
-function ll { Get-ChildItem -Force | Format-Table -AutoSize }
-function la { Get-ChildItem -Force }
-function l { Get-ChildItem }
+# Directory listing - lsd (modern ls replacement)
+function ls { lsd $args }
+function l { lsd -l $args }
+function la { lsd -a $args }
+function lla { lsd -la $args }
+function lt { lsd --tree $args }
+function ll { lsd -AlFh $args }
 
 # Reload shell profile
 function es { & $PROFILE }