refactor: migrate from shell-based sync to mise dotfiles management

- Replace sync-config/sync-script with mise.toml [dotfiles] directives
- Convert installer scripts to mise tasks (shells, desktop, theme, webapps)
- Remove config/nvim-old (deprecated neovim config)
- Add omarchy theme system with multi-app configs (btop, hyprland, kitty, foot, tmux, etc.)
- Move SSH hosts to config.d/* include pattern
- Add Tera templates for dynamic config generation (git-local, dofiles.conf)
- Update pi agent settings (0.80.10, packages list)
- Add mise tasks for pi plugin setup and nvim tooling

config/ssh/config

@@ -1,27 +1,2 @@
-SetEnv TERM=xterm-256color
+Include config.d/*
 
-Host dupont 
-    HostName 172.25.11.30
-    user sjb
-    ForwardAgent yes
-    RemoteForward /run/user/1000/gnupg/S.gpg-agent /run/user/1000/gnupg/S.gpg-agent.extra
-    StreamLocalBindUnlink yes
-    RequestTTY yes
-
-Host haddock-tmux
-    User sjb
-    Hostname 129.100.33.96
-    ForwardAgent yes
-    RemoteForward /run/user/1000/gnupg/S.gpg-agent /run/user/1000/gnupg/S.gpg-agent.extra
-    StreamLocalBindUnlink yes
-    RequestTTY yes
-    RemoteCommand tmux -l new -A
-
-Host risc-v
-    User sjb
-    Hostname 172.25.11.31
-    ForwardAgent yes
-    RemoteForward /run/user/1001/gnupg/S.gpg-agent /run/user/1000/gnupg/S.gpg-agent.extra
-    StreamLocalBindUnlink yes
-    RequestTTY yes
-