feat(core): Support P2PK payment request sends

[igbopharaoh]

Description

This pull request adds payer-side NUT-18 P2PK payment request support using cashu-ts NUT-10/NUT-11 normalization. #286

Problem

Coco could parse and pay normal payment requests, but P2PK requests needed explicit NUT-11 mint support checks, locked-output send preparation, and clear failure behavior for malformed or unsupported spending conditions before funds move.

Summary

• Adds normalized P2PK payment request requirements, NUT-11 payable-mint filtering, and prepare-time NUT-11 assertions.
• Routes payment request P2PK sends through the general P2PK send handler with structured cashu-ts options.
• Keeps HTTP/inband/Nostr delivery semantics unchanged and documents the new payer-side behavior.
• Adds adapter contract coverage for structured send method persistence.

Verification

• bun run --filter='@cashu/coco-core' test -- test/unit/PaymentRequestService.test.ts
• bun run --filter='@cashu/coco-core' test -- test/unit/P2pkSendHandler.test.ts test/unit/SendOpsApi.test.ts test/unit/MintService.test.ts
• bun run --filter='@cashu/coco-core' test:unit
• bun run typecheck
• bun run docs:build
• git diff --check

Changeset

• Added .changeset/p2pk-payment-requests.md.

[changeset-bot]

🦋 Changeset detected

Latest commit: cfb2822

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 8 packages

Name	Type
@cashu/coco-core	Major
@cashu/coco-adapter-tests	Major
@cashu/coco-indexeddb	Major
@cashu/coco-expo-sqlite	Major
@cashu/coco-sql-storage	Major
@cashu/coco-sqlite	Major
@cashu/coco-sqlite-bun	Major
@cashu/coco-react	Major

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[Egge21M]

Thank you fr taking this on. The direction is great and this is almost good to go. There are a could docs missing and an issue with how cashu-ts' P2PKOptions behave currently. Please take a look at the comments

[Egge21M]

This can throw if a single mint is offline and take the whole call with it. I think we should catch single mint failures and simply exclude them from the request.

[igbopharaoh]

Thank you fr taking this on. The direction is great and this is almost good to go. There are a could docs missing and an issue with how cashu-ts' P2PKOptions behave currently. Please take a look at the comments

Thanks for the review, I'll attend to all the comments now

[Egge21M]

Thanks for the quick changes. Unfortunately I did find one more issue, which is a bit of a gotcha introduced by CTS.

[Egge21M]

Cashu-TS lets you add a hashLock on a P2PK construction, which turns the resulting data into HTLC (NUT-14) data. HTLC is out-of-scope for now, so we should make sure that consumers can't add it here.

[igbopharaoh]

Great, addressing it now