feat: add cart infering, update tracking documentation

[dkonieczek]

No description provided.

[Copilot]

Pull Request Overview

This PR introduces cart inference functionality in the tracker along with comprehensive updates to tracking documentation across multiple packages.

• Adds a new optional cart property to the tracker globals and processes cart updates in the tracker logic.
• Extends tests to validate cart inference behavior.
• Updates documentation for tracking events and context to align with the new cart and event structures.

Reviewed Changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
packages/snap-tracker/src/types.ts	Adds an optional cart array to the tracker globals and imports the Product type.
packages/snap-tracker/src/Tracker.ts	Implements cart inference: comparing current vs. stored cart to trigger add/remove events and sends error notifications for invalid cart objects.
packages/snap-tracker/src/Tracker.test.ts	Introduces tests covering various cart scenarios including empty carts, addition, removal, and error handling.
packages/snap-preact/src/Snap.tsx	Merges cart data from shopper context into tracker globals and removes legacy cookie population.
packages/snap-preact/src/Snap.test.tsx	Adjusts tests to validate tracker storage cart updates reflecting the new cart inference feature.
docs/* and packages/snap-controller/*	Updates tracking documentation and event naming across multiple controllers and integration guides.