fix(core): dedupe proof watcher finalization checks

[Egge21M]

Description

This pull request fixes redundant proof watcher send finalization checks.

Problem

Spent proof handling could trigger repeated send finalization work for the same operation. A subscription-driven spent notification already emitted a proof state event that finalized the send, and batched spent events could also repeat the operation-level check once per proof from the same send operation.

Summary

• Remove the direct subscription callback finalization path and let proof state events own send finalization.
• Deduplicate candidate send operation IDs within a single spent-proof event before running the all-spent finalization check.
• Add focused watcher tests for subscription notifications, same-operation batched events, and multi-operation batched events.
• Add/update the core patch changeset.

Verification

• bun run --filter='@cashu/coco-core' test -- test/unit/ProofStateWatcherService.test.ts
• bun run --filter='@cashu/coco-core' test -- test/unit/SendOperationService.test.ts
• bun run --filter='@cashu/coco-core' typecheck
• git diff --check

Changeset

• .changeset/single-proof-finalization.md

[changeset-bot]

🦋 Changeset detected

Latest commit: b6093f4

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

This PR includes changesets to release 7 packages

Name	Type
@cashu/coco-core	Patch
@cashu/coco-adapter-tests	Patch
@cashu/coco-expo-sqlite	Patch
@cashu/coco-indexeddb	Patch
@cashu/coco-react	Patch
@cashu/coco-sqlite-bun	Patch
@cashu/coco-sqlite	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 84.94%. Comparing base (c321b30) to head (b6093f4).

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #180      +/-   ##
==========================================
+ Coverage   84.29%   84.94%   +0.65%     
==========================================
  Files         115      115              
  Lines       13928    13915      -13     
==========================================
+ Hits        11740    11820      +80     
+ Misses       2188     2095      -93     

Flag	Coverage Δ
core-integration	54.01% <ø> (ø)
core-unit	88.28% <100.00%> (+0.72%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.