Add core inspector, CLI, and formatter

- Inspector extracts callbacks and validators from any AR model,
  resolves source locations, and filters Rails internals
- CLI: `whetrails inspect <ModelName>` boots Rails and renders chain
- Formatter produces clean lifecycle-ordered terminal output
- Order model added as development fixture

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/whetrails.rb

@@ -0,0 +1,9 @@
+require_relative "whetrails/version"
+require_relative "whetrails/chain"
+require_relative "whetrails/inspector"
+
+module Whetrails
+  def self.inspect_model(model_class)
+    Inspector.inspect_model(model_class)
+  end
+end