Update documentation to support both mise and asdf version managers

The documentation previously required asdf, but mise is now the recommended
modern alternative. Updated to support both version managers with mise as
the recommended option.

Changes:
- Add mise installation instructions alongside asdf
- Update all commands to show mise equivalents
- Clarify that mise reads from mise.toml (no plugin installation needed)
- Update troubleshooting section for both version managers

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

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

Author: justin808

SWITCHING_CI_CONFIGS.md

@@ -53,15 +53,20 @@ The project runs tests against two configurations:
 
 ## Prerequisites
 
-You must have [asdf](https://asdf-vm.com/) installed to manage Ruby and Node versions.
+You must have a version manager like [mise](https://mise.jdx.dev/) (recommended) or [asdf](https://asdf-vm.com/) installed to manage Ruby and Node versions.
 
 ```bash
-# Install asdf if needed (macOS with Homebrew)
+# Install mise (recommended, modern alternative to asdf)
+brew install mise
+echo 'eval "$(mise activate zsh)"' >> ~/.zshrc
+source ~/.zshrc
+
+# OR install asdf (legacy option)
 brew install asdf
 echo -e "\n. $(brew --prefix asdf)/libexec/asdf.sh" >> ~/.zshrc
 source ~/.zshrc
 
-# Install plugins
+# Install plugins (only needed for asdf, mise reads from mise.toml)
 asdf plugin add ruby
 asdf plugin add nodejs
 ```
@@ -102,7 +107,7 @@ This will:
 ```bash
 # Reload your shell to pick up new Ruby/Node versions
 cd /Users/justin/conductor/react_on_rails/.conductor/kuwait-v1
-asdf current
+mise current  # or: asdf current
 
 # Build and test
 rake node_package
@@ -132,7 +137,7 @@ This will:
 ```bash
 # Reload your shell to pick up new Ruby/Node versions
 cd /Users/justin/conductor/react_on_rails/.conductor/kuwait-v1
-asdf current
+mise current  # or: asdf current
 
 # Build and test
 rake node_package
@@ -210,19 +215,27 @@ bin/ci-switch-config latest
 
 ## Troubleshooting
 
-### "asdf: No version is set for ruby"
+### "No version is set for ruby" or version didn't change
 
 After switching, you need to reload your shell:
 
 ```bash
 cd /Users/justin/conductor/react_on_rails/.conductor/kuwait-v1
-# The cd command will trigger asdf to load the new versions
+# The cd command will trigger mise/asdf to load the new versions
 ruby --version  # Verify it changed
 ```
 
 ### Ruby/Node version didn't change
 
-If asdf doesn't automatically switch:
+If your version manager doesn't automatically switch:
+
+**For mise:**
+
+```bash
+mise install  # Install missing versions from mise.toml or .tool-versions
+```
+
+**For asdf:**
 
 ```bash
 asdf install  # Install missing versions from .tool-versions