fix(workflow): use direct prompt instead of slash command for Claude Code CLI

CLI -p flag does not resolve skills/slash commands — only the interactive
REPL does. Pass a plain prompt instructing Claude to read and execute
commands/assign-reviewers.md directly.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: shadowdevcode

.github/workflows/pr-auto-review.yml

@@ -33,4 +33,4 @@ jobs:
           SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
         run: |
           claude --dangerously-skip-permissions \
-            -p "/assign-reviewers ${{ github.event.pull_request.html_url }}"
+            -p "Read commands/assign-reviewers.md and execute the full protocol for this PR: ${{ github.event.pull_request.html_url }}"