ci: run scope probe from diagnostic PR

Refs #645.

AIDD-Session-Id: 01a0ca9a-53ab-7ec2-bdc8-d6a3b3ae164c

Author: blafourcade

.github/workflows/claude-project-scope-probe.yml

@@ -2,12 +2,15 @@ name: Claude project scope probe
 
 on:
   workflow_dispatch:
+  pull_request:
+    branches: [next]
 
 permissions:
   contents: read
 
 jobs:
   windows:
+    if: github.event_name == 'workflow_dispatch' || github.head_ref == 'chore/claude-windows-scope-probe'
     runs-on: windows-latest
     defaults:
       run: