Add Zeitwerk eager loading check to CI

Adds validation that Zeitwerk can eager load all files without errors.
This catches autoloading issues like inflector bugs and missing
conditional checks before they reach production.

- Added check after linter step for fast fail
- Runs on all Ruby/Rails matrix combinations
- ~2 second check prevents production crashes

## Blocked

This PR depends on crmne#504 (ActiveRecord dependency fix) to pass.
Without it, the eager loading check fails with NameError.

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

Co-Authored-By: Claude <[email protected]>

Author: trevorturk

.github/workflows/cicd.yml

@@ -68,6 +68,9 @@ jobs:
     - name: Check code format
       run: bundle exec rubocop
 
+    - name: Check Zeitwerk eager loading
+      run: bundle exec ruby -e "require 'ruby_llm'; Zeitwerk::Loader.eager_load_all"
+
     - name: Run tests
       if: matrix.ruby-version != '3.4' || matrix.rails-version != 'rails-8.0'
       run: bundle exec appraisal ${{ matrix.rails-version }} rspec --tag '~generator'