Dw Checkout Guard

Version bump alongside 667cf8e, which replaced the stale Shopify scaffold
fixtures with five real behaviour tests run against the compiled
function.wasm. Lint + review pass this session found nothing further to fix
in the fixtures (all parse, all internally consistent with their filenames).

The function is now installed and Active on the live store
(designer-laboratory-sandbox, checkout rule 82837555, fail-open).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

The repo shipped Shopify's default cart-validation scaffold fixtures
(quantity-is-one / quantity-exceeds-one). They carry only a quantity
field, so they do not satisfy this function's input query (which reads
cost.amountPerQuantity and merchandise.product.isDiscontinued) and
validateTestAssets failed 2/2 — i.e. the guard shipped with a test suite
that had never once exercised the guard.

Replaced with five fixtures run against the real compiled function.wasm:

  dw-zero-price-BLOCKS              $0.00 Per Yard      -> blocked
  dw-sample-only-ALLOWS             $4.25 Sample        -> ALLOWED
  dw-mixed-zero-plus-sample-BLOCKS  $0 + $4.25          -> blocked
  dw-discontinued-BLOCKS            discontinued tag    -> blocked
  dw-zero-plus-discontinued-MIXED   both                -> mixed message

The allow case is the load-bearing one: this cohort must keep its $4.25
sample flow working, so a guard that blocked everything would be worse
than no guard. 5/5 pass.

TK-11301. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XA7ZPurwcdipst1gsgwwXq

Rebuilt the function extension from the current CLI's cart_checkout_validation scaffold
(the original was old-style: missing src/index.js entry -> JS undetected, camelCase TOML
export, no codegen package.json). Overlaid the hardened $0/discontinued logic + input query,
regenerated types, built with javy, VERIFIED locally ($0 line -> validationAdd error; $50 line
-> operations:[]), and released version dw-checkout-guard-2 to the linked DW Partner app.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>