Fix GitHub Release permissions in release workflow

[RAprogramm]

Fix permissions error preventing GitHub Release creation.

Problem

Release workflow fails at 'Create GitHub Release' step with 403 error:

Resource not accessible by integration

Root Cause

Missing permissions: contents: write in release.yml workflow

Impact

• crates.io publish: WORKS ✅
• GitHub Release: FAILS ❌

Solution

Add permissions block to release.yml:

permissions:
  contents: write

Testing

Create new annotated tag (e.g., v0.1.1) to verify GitHub Release creation works