chore: untrack .agentworkforce internal tooling, add to gitignore

The personas JSON got swept into the previous commit by `git add -A`.
It's local AgentWorkforce workforce tooling, not part of the public
site repo. Removes it from the index and ignores the directory so
future commits don't pick it up.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: khaliqgant

.agentworkforce/workforce/personas/education-seo-geo-blog-operator.json

@@ -40,6 +40,9 @@ yarn-error.log*
 .wrangler/
 .dev.vars
 
+# AgentWorkforce internal tooling (not site content)
+.agentworkforce/
+
 # typescript
 *.tsbuildinfo
 next-env.d.ts