chore: remove materialized plugin files from tracking

These agents/, commands/, and skills/ directories inside plugin folders
are generated by eng/materialize-plugins.mjs during CI publish and
should not be committed to the staged branch.

- Remove 185 materialized files from git tracking
- Add .gitignore rules to prevent accidental re-commits
- Update publish.yml to force-add materialized files despite .gitignore

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: aaronpowell

.github/workflows/publish.yml

@@ -49,5 +49,6 @@ jobs:
           git config user.name "github-actions[bot]"
           git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
           git add -A
+          git add -f plugins/*/agents/ plugins/*/commands/ plugins/*/skills/
           git commit -m "chore: publish from staged [skip ci]" --allow-empty
           git push origin HEAD:main --force

.gitignore

@@ -10,6 +10,11 @@ reports/
 # Generated files
 /llms.txt
 
+# Materialized plugin files (generated by CI via eng/materialize-plugins.mjs)
+plugins/*/agents/
+plugins/*/commands/
+plugins/*/skills/
+
 # Website build artifacts
 website/dist/
 website/.astro/