WA-VERIFY-058: Add repo-root Zeitwerk autoload check script

[kitcommerce]

Summary

Zeitwerk autoloading is sensitive to naming conventions and engine structure. A dedicated repo-root script would let contributors quickly verify Zeitwerk is happy before pushing.

Objective

Add a bin/verify-zeitwerk (or scripts/verify-zeitwerk.sh) script that:

• Runs bin/rails zeitwerk:check (or equivalent) under the default appraisal
• Reports pass/fail clearly
• Can be run from the repo root without knowing the engine layout

Acceptance Criteria

• Script exists at scripts/verify-zeitwerk.sh (or bin/verify-zeitwerk)
• Script runs zeitwerk:check against the default appraisal Ruby version
• Script outputs clear pass/fail summary
• Script is referenced in the scripts index (see WA-VERIFY-033 / WA-DOC-007)

Verification Plan

• Run the script; confirm it outputs a clear result
• Confirm it's referenced in the doc index

Client Impact

None (developer tooling only).

[kitcommerce]

PR opened: #1028

Adds scripts/verify-zeitwerk.sh — a portable Bash script that runs zeitwerk:check against all three engine dummy apps (core, admin, storefront) with colour-coded pass/fail output. Also adds docs/verification-index.md (WA-DOC-007) as the central scripts index.