Remove JSL source from default registry

The default plugin ships with only the ce-default reviewer source.
Users add their own sources via ~/.config/compound-engineering/reviewer-sources.yaml.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: jcasimir

plugins/compound-engineering/skills/ce-review/references/reviewer-registry.yaml

@@ -25,10 +25,6 @@
 #   except  — List of reviewer filenames (without .md) to skip from this source
 
 sources:
-  - name: jsl-reviewers
-    repo: JumpstartLab/ce-reviewers-jsl
-    branch: main
-    path: .
   - name: ce-default
     repo: JumpstartLab/ce-reviewers
     branch: main