feat(mise): Generate toolbox conf.d files dynamically from tools.yaml

Toolboxes declared in .chezmoidata/tools.yaml no longer need a matching
source file under private_dot_config/mise/conf.d/. The run_onchange
install script now loops over tools.yaml/hosts.yaml directly to
(re)generate ~/.config/mise/conf.d/<toolbox>.toml, and removes files for
toolboxes no longer assigned to the host/user, so mise config.toml stays
limited to individual, non-toolbox tools.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GA4dAzARMnLz1G9AmQkYYn

run_once_after_00-install-mise.sh.tmpl

@@ -15,7 +15,7 @@ if command -v mise &>/dev/null; then
     mise bootstrap --yes
 fi
 
-# 3. Installer tous les outils déclarés dans ~/.config/mise/config.toml
+# 3. Installer tous les outils déclarés dans ~/.config/mise/config.toml et ~/.config/mise/conf.d/*.toml
 if command -v mise &>/dev/null; then
     echo "⚡ Installation des outils via Mise (dont chezmoi si désiré)..."
     mise install --yes