Proposal: Trade and supply chain docs example audit and update

Related to #596.

## Summary

I would like to work on the Trade & Supply Chain documentation example update. My proposal is to start with a concrete audit of the current IOTA Docs examples, then update the relevant examples so they follow one consistent trade and supply chain scenario without changing the docs structure unnecessarily.

## Proposed scenario

Use an international shipment flow:

- Customs Authority as the trust/root authority
- Exporter as the licensed producer or shipper
- Freight Forwarder as the logistics operator
- Customs Broker as the clearance actor
- Importer as the receiving party

This maps naturally to the Trust Framework components:

- Identity: actor DIDs and trade/license credentials
- Hierarchies: authority-to-operator delegation chain
- Notarization: bill of lading, certificate of origin, custody transfer, and clearance events
- Gas Station: sponsored updates by logistics actors
- Tokenization: container or shipment certificate as a tracked on-chain asset

## Deliverables

1. Audit the existing docs/examples and produce a short file-path map of what needs to change.
2. Update code snippets and surrounding text to use the shipment scenario consistently.
3. Preserve the existing teaching flow and API patterns where possible.
4. Add or update any lightweight validation notes needed to show the examples are current.
5. Submit a PR referencing this proposal and #596.

## Scope control

I will avoid large unrelated rewrites. If the audit shows that examples live across multiple repositories or that some SDK examples are generated from another source, I will call that out first and keep the PR focused on the source of truth.

## Initial work plan

- Day 1: audit docs/example locations and identify exact source files
- Day 2-3: update the highest-impact examples and companion text
- Day 4: run available docs/example validation and polish the PR
- Day 5: respond to review feedback

If this direction looks good, I will proceed with the audit and then open the implementation PR.