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>

db/migrate/20260608161002_create_orders.rb

@@ -0,0 +1,10 @@
+class CreateOrders < ActiveRecord::Migration[8.1]
+  def change
+    create_table :orders do |t|
+      t.string :status
+      t.decimal :total
+
+      t.timestamps
+    end
+  end
+end