fix: add id-token: write permission to Claude review workflow

[Dhwanil25]

Problem

The Claude Code Action was failing with:

Could not fetch an OIDC token. Did you remember to add `id-token: write` to your workflow permissions?

Fix

Added id-token: write to the job permissions in .github/workflows/claude-review.yml.

Before

permissions:
  contents: read
  pull-requests: write

After

permissions:
  contents: read
  pull-requests: write
  id-token: write

Note: You also need ANTHROPIC_API_KEY set in repo Settings → Secrets and variables → Actions for the action to authenticate with Anthropic.

🤖 Generated with Claude Code

[Dhwanil25]

Closing — merging this fix into PR #13 to keep everything in one branch.