Add rvm and nvm support to ci-switch-config (#1986)

## Summary

- Add support for rvm (Ruby Version Manager) and nvm (Node Version
Manager) to the `bin/ci-switch-config` script
- Previously only supported mise and asdf version managers
- Makes the script more flexible for developers using different version
management tools

## Key Changes

- Enhanced `check_version_manager()` to detect rvm, nvm, or rvm+nvm
combinations
- Added `set_ruby_version()` helper function to switch Ruby versions
with rvm
- Added `set_node_version()` helper function to switch Node versions
with nvm
- Updated `switch_to_minimum()` to use new helper functions
- Updated `restore_to_latest()` to use new helper functions
- Added appropriate shell reload/verification instructions for each
version manager

## How It Works

The script now detects version managers in this priority order:
1. mise (recommended)
2. asdf
3. rvm + nvm (both installed)
4. rvm only
5. nvm only

For rvm/nvm users:
- Automatically installs missing Ruby/Node versions if needed
- Sources nvm if not already loaded in the environment
- Uses `rvm use` and `nvm use` to switch versions
- Provides appropriate verification commands

## Test Plan

- [x] Syntax validation passes (`bash -n bin/ci-switch-config`)
- [x] Status command works correctly
- [x] RuboCop passes with zero offenses
- [x] Pre-commit hooks pass
- [x] File ends with proper newline

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

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<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* Support for multiple version managers (mise, asdf, rvm, nvm),
including mixed rvm+nvm setups, with per-manager flows to set/apply Ruby
and Node and status visibility for runtimes.
* **Bug Fixes**
* Improved messaging and error handling when managers or versions are
missing; clearer manager-specific reload/current-version guidance.
* **Documentation**
* Revised switching guide with setup options, rvm+nvm notes,
manager-specific commands, examples, and expanded troubleshooting.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: Claude <noreply@anthropic.com>

Author: justin808

SWITCHING_CI_CONFIGS.md

@@ -53,24 +53,53 @@ The project runs tests against two configurations:
 
 ## Prerequisites
 
-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.
+You must have a version manager installed to manage Ruby and Node versions. The script supports:
+
+- **[mise](https://mise.jdx.dev/)** - Recommended, modern, manages both Ruby and Node
+- **[asdf](https://asdf-vm.com/)** - Legacy option, manages both Ruby and Node
+- **[rvm](https://rvm.io/) + [nvm](https://github.com/nvm-sh/nvm)** - Separate managers for Ruby and Node
+
+### Option 1: mise (Recommended)
 
 ```bash
-# Install mise (recommended, modern alternative to asdf)
+# Install mise
 brew install mise
 echo 'eval "$(mise activate zsh)"' >> ~/.zshrc
 source ~/.zshrc
 
-# OR install asdf (legacy option)
+# mise automatically reads from .tool-versions
+```
+
+### Option 2: asdf
+
+```bash
+# Install asdf
 brew install asdf
 echo -e "\n. $(brew --prefix asdf)/libexec/asdf.sh" >> ~/.zshrc
 source ~/.zshrc
 
-# Install plugins (only needed for asdf, mise reads from mise.toml)
+# Install plugins
 asdf plugin add ruby
 asdf plugin add nodejs
 ```
 
+### Option 3: rvm + nvm
+
+```bash
+# Install rvm for Ruby
+\curl -sSL https://get.rvm.io | bash -s stable
+source ~/.rvm/scripts/rvm
+
+# Install nvm for Node
+curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.39.0/install.sh | bash
+# Add to shell config (the installer usually does this automatically)
+```
+
+**Important Notes:**
+
+- If you only have rvm (no nvm) or only nvm (no rvm), the script will detect this and provide helpful error messages guiding you to install the missing manager or switch to mise/asdf.
+- **Do not mix version managers** (e.g., don't install both mise and rvm). The script prioritizes mise > asdf > rvm+nvm, so mise/asdf will always take precedence. Using multiple managers can cause confusion about which versions are active.
+
 ## Detailed Usage
 
 ### 1. Check Current Configuration
@@ -107,7 +136,9 @@ This will:
 ```bash
 # Reload your shell to pick up new Ruby/Node versions
 cd <project-root>
-mise current  # or: asdf current
+mise current           # For mise users
+# asdf current         # For asdf users
+# rvm current && nvm current  # For rvm+nvm users
 
 # Build and test
 rake node_package
@@ -137,7 +168,9 @@ This will:
 ```bash
 # Reload your shell to pick up new Ruby/Node versions
 cd <project-root>
-mise current  # or: asdf current
+mise current           # For mise users
+# asdf current         # For asdf users
+# rvm current && nvm current  # For rvm+nvm users
 
 # Build and test
 rake node_package
@@ -243,6 +276,22 @@ asdf reshim ruby
 asdf reshim nodejs
 ```
 
+**For rvm + nvm:**
+
+```bash
+# Install and use specific Ruby version
+rvm install 3.2.8   # or 3.4.3
+rvm use 3.2.8
+
+# Install and use specific Node version
+nvm install 20.18.1  # or 22.12.0
+nvm use 20.18.1
+
+# Verify versions
+ruby --version
+node --version
+```
+
 ### Yarn install fails
 
 If you get package resolution errors: