Cross chain announcement

[clintjeff2]

Motivation

• Provide a single source-of-truth documenting announcement event/args schemas across supported chains so the SDK can normalize without ad-hoc special-casing.
• Surface every encoding divergence and recommend a canonical normalized Announcement type for the SDK to consume.
• Add a minimal on-chain-side unit test to prove the CKB lock-arg slicing semantics used for announcements round-trip in this repo.

Description

• Add ANNOUNCEMENT_SCHEMA.md at the repo root containing a field-by-field matrix for EVM, Stellar, Solana, and CKB, severity-tagged findings, canonical SDK Announcement recommendation, source-of-truth links, and alignment recommendations.
• Add a CKB unit test parse_lock_args_roundtrip in ckb/contracts/wraith-stealth-lock/src/main.rs that validates the ephemeral_pubkey ([0..33]) and blake160(stealth_pubkey) ([33..53]) slicing assumptions.
• Update ckb/Cargo.lock (dependency snapshot changed by running tests/compilation).
• Document that the expected SDK decoder path (sdk/src/chains/*/announcements.ts) is not present in this snapshot, so SDK-code linking was not possible from this repo alone.

Testing

• Ran cd ckb/contracts/wraith-stealth-lock && cargo test and the new test tests::parse_lock_args_roundtrip passed (1 passed).
• Ran cd stellar/stealth-announcer && cargo test and existing tests passed (2 passed).

---

Closes #12

[drips-wave]

@clintjeff2 Great news! 🎉 Based on an automated assessment of this PR, the linked Wave issue(s) no longer count against your application limits.

You can now already apply to more issues while waiting for a review of this PR. Keep up the great work! 🚀

Learn more about application limits

[clintjeff2]

@truthixify Please review and merge

[truthixify]

The schema doc is good — clean per-field matrix, severity-tagged findings, and the split between "harmless to align" vs "intentional" divergences makes the canonical SDK form a real outcome rather than just description. Calling out the ephemeralPubKey size mismatch (33 vs 32 across chains) is the kind of finding that would silently bite us later.

One note: the SDK-side conformance tests called out in the issue spec live in a separate repo and are already tracked over there as wraith-protocol/sdk#8. The new CKB slice-roundtrip test is fine to keep but doesn't really cover that ask — no action needed.

Merging. Thanks @clintjeff2.