ci: widen the path filter to tools/

The filter still named check-branding.sh at the repo root, a path that no
longer exists after the move — so a change to the branding toolkit would
not have triggered CI at all. Silent, and exactly the failure the toolkit
exists to prevent elsewhere.

'tools/**' also covers the deploy scripts that will land there.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WHt4DykxXaQnyaJfyS8KCn

.github/workflows/ci.yaml

@@ -9,7 +9,7 @@ on:
       - 'Cargo.toml'
       - 'Cargo.lock'
       - 'bundler.toml'
-      - 'check-branding.sh'
+      - 'tools/**'
   pull_request:
     branches: [ master ]
   workflow_dispatch: