chore: stellar and hedera scripts

[Deiadara]

why

Had to manually construct proof for hedera so I documented the process, also updated the stellar script and readme which was outdated.

how

---

Note

Low Risk
Mostly documentation and developer scripts; the only behavior change is a small CLI argument/default tweak for Stellar change-trust with limited blast radius.

Overview
Adds a new runbook (evm/docs/manual-proof-construction.md) describing how to manually unblock stuck Amplifier hub-routed messages by constructing a MultisigProver proof, polling for completion, submitting it to the destination EVM gateway, and optionally manually calling ITS.execute() (includes a Hedera testnet worked example and session-id quoting gotcha).

Introduces scripts/construct-proof-hedera.js, a self-contained script that triggers construct_proof for a specific axelar→hedera message, extracts/normalizes the multisig_session_id, and polls until the proof is completed.

Fixes Stellar tooling/docs by making stellar/token-utils.js change-trust accept an optional [limit] (defaulting to 1000000000) and aligning the stellar/README.md example accordingly.

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