Restore id-token: write for claude-code-action OIDC

Removed earlier as 'unused'. anthropics/claude-code-action@v1 needs
id-token: write to fetch an OIDC token. Skill step was failing with
"Could not fetch an OIDC token" on the first real dispatch.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: rdimitrov

.github/workflows/upstream-release-docs.yml

@@ -47,6 +47,8 @@ on:
 permissions:
   contents: write
   pull-requests: write
+  # Required by anthropics/claude-code-action@v1 for OIDC token exchange.
+  id-token: write
 
 concurrency:
   # Workflow-level group so two simultaneous upstream releases don't