Run Tests on PRs regardless of base branch

`branches: ['*']` looks like "all branches" but the `*` glob does not
match `/`, so the Tests workflow silently skipped any PR whose base
branch contains a slash (e.g. a stacked PR based on another PR's
claude/... branch). Drop the filter; a bare pull_request trigger covers
every base branch.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

https://claude.ai/code/session_01JHvKryT4QUpHYdNq9YEQxX

Author: claude

.github/workflows/tests.yml

@@ -1,8 +1,9 @@
 name: Tests
 
+# No branch filter: `branches: ['*']` would skip PRs whose base branch
+# contains a slash, since the `*` glob does not match `/`.
 on:
   pull_request:
-    branches: ['*']
 
 jobs:
   unit-tests: