Canary failure: JavaScriptKit 0.55.0 breaks build

[github-actions]

Upstream Contract Breakage Detected

The weekly canary job failed to build OpenCombineJS against JavaScriptKit 0.55.0.

Likely causes (from 05-contract-tests.md risk catalog)

• JSValueDecoder duplicate TopLevelDecoder conformance — R1 (issue JSValueDecoder: document retroactive TopLevelDecoder conformance risk + canary monitor #9)
• JSPromise.then(success:failure:) signature change — R2
• JSTimer reference-semantics change — R3
• OpenCombine Swift 6 Sendable incompatibility — R5

Action required

1. Review the canary workflow run.
2. If R1 (duplicate conformance): delete Sources/OpenCombineJS/JSValueDecoder.swift and bump the minor version.
3. If R2/R3: update the affected bridging code.
4. Open a migration issue linked here and milestone it to the next sprint.

Run ID: 27532044950

[github-actions]

Canary re-triggered on run 27937958091: https://github.com/IGRSoft/OpenCombineJS/actions/runs/27937958091