Add pull-requests read permission for identifiers workflow

**Issue:**
The identifiers workflow requires pull-requests: read permission
to determine release type, but was denied by workflow permissions.

**Fix:**
Added pull-requests: read to workflow-level permissions block.

**Error:**
Invalid workflow file: .github/workflows/release.yml#L18
The nested job 'build-identifiers' is requesting 'pull-requests: read',
but is only allowed 'pull-requests: none'.

Author: oberstet

.github/workflows/release.yml

@@ -13,6 +13,7 @@ permissions:
   id-token: write      # Required for PyPI trusted publishing (OIDC)
   contents: write      # Required for creating GitHub releases
   discussions: write   # Required for posting to discussions
+  pull-requests: read  # Required for identifiers workflow
 
 jobs:
   identifiers: