Updates edit-issue-labels.sh and comment-on-duplicates.sh to read the
issue number from GITHUB_EVENT_PATH (the workflow event payload) instead
of accepting it as a CLI argument. Simplifies the call signature and
keeps the scripts aligned with the triggering issue.
Also updates the /triage-issue and /dedupe command docs to match.
🏠 Remote-Dev: homespace
Extract triage prompt into /triage-issue command and use a dedicated
edit-issue-labels.sh script for label operations instead of raw
gh issue edit. The script validates labels against the repo's existing
labels before applying them.