refactor: update ecommerce module to TS

[jaissica12]

Background

• Migrate remaining JavaScript modules to TypeScript for improved type safety and developer experience across the SDK codebase.

What Has Changed

• Converted src/ecommerce.js to src/ecommerce.ts with full type annotations on all methods and parameters
• Converted test/src/tests-eCommerce.js to test/src/tests-eCommerce.ts with necessary type casts for intentional type-mismatch tests that validate error handling

Screenshots/Video

• Add to Cart

• Purchase

Checklist

• I have performed a self-review of my own code.
• I have made corresponding changes to the documentation.
• I have added tests that prove my fix is effective or that my feature works.
• I have tested this locally.

Additional Notes

• var declarations replaced with const/let (SonarCloud compliance)
• ShoppingCart initialization corrected from [] to {} to align with SDKShoppingCart interface type
• No functional/behavioral changes

Reference Issue (For employees only. Ignore if you are an outside contributor)

• Closes https://go/j/SDKE-1108

[cursor]

PR Summary

Medium Risk
Commerce event creation and expansion are customer-facing; the ShoppingCart shape change from [] to {} is the main runtime surface worth validating in integration tests even though the PR targets parity.

Overview
Migrates the eCommerce implementation and its test suite from JavaScript to TypeScript, wiring the constructor and methods to IECommerce, @mparticle/event-models, and sdkRuntimeModels types instead of untyped parameters.

The module now uses typed const/let, arrow/forEach callbacks with explicit product/promotion types, and a _self indirection so internal helpers stay callable from expansion paths where this would otherwise break. createCommerceEventObject initializes ShoppingCart as an empty object (SDKShoppingCart) rather than an array. Tests move to .ts with Function casts where they deliberately pass invalid inputs, and they reference ProductActionType / PromotionActionType from test constants instead of mParticle.* aliases.

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[cursor]

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[sonarqubecloud]

Quality Gate failed

Failed conditions
10.3% Duplication on New Code (required ≤ 3%)

See analysis details on SonarQube Cloud