What Happened
- The PR fixes a deterministic CI breakage by correcting the vendoring sync config for the slack-channel plugin: test files were excluded while `bun test` was still kept, causing `No tests found!` failures. The change updates `sources.yaml` so upstream `features/**` test suites are included and runnable in the mirror.
- The PR fixes a deterministic CI breakage by correcting the vendoring sync config for the slack-channel plugin: test files were excluded while `bun test` was still kept, causing `No tests found!` failures. The change updates `sources.yaml` so upstream `features/**` test suites are included and runnable in the mirror.
- 1 evidence item attached for review.