Add a worked example walking through registering a test phone hash on testnet

[chillwur]

Description

A single end-to-end narrative (not just isolated command snippets) helps a newcomer understand the full flow once.

Deliverables

• A walkthrough (in examples/ or docs/INTEGRATION.md) showing: computing a phone hash, funding a testnet identity, calling register, then calling resolve to confirm it worked.

Depends on

Add an example stellar contract invoke command for register, Add an example stellar contract invoke command for resolve