Fix Discord release webhook failing on large changelogs

- Pin action to v1.19.0 for stability
- Add remove_github_reference_links to strip commit hash section
- Fixes embed validation error from oversized release notes

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

.github/workflows/discord-release.yml

@@ -12,7 +12,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Send to Discord
-        uses: SethCohen/github-releases-to-discord@v1
+        uses: SethCohen/github-releases-to-discord@v1.19.0
         with:
           webhook_url: ${{ secrets.DISCORD_WEBHOOK_URL }}
           color: "5865F2"
@@ -21,4 +21,5 @@ jobs:
           footer_title: "Auto Claude Changelog"
           footer_timestamp: true
           reduce_headings: true
+          remove_github_reference_links: true