fix: pass GITHUB_TOKEN to implement workflow for push permissions

Claude couldn't push branches because the OAuth token from the GitHub
App may not have contents:write. Explicitly pass the workflow's
GITHUB_TOKEN (which has contents:write from job permissions) so git
push and gh pr create work.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: minitriga

.github/workflows/claude-implement.yml

@@ -78,6 +78,7 @@ jobs:
         uses: anthropics/claude-code-action@v1
         with:
           claude_code_oauth_token: ${{ secrets.CLAUDE_CODE_OAUTH_TOKEN }}
+          github_token: ${{ secrets.GITHUB_TOKEN }}
           claude_args: >-
             --model claude-sonnet-4-20250514
             --max-turns 50