fix: resolve JS-005, JS-006, SVC-006 architecture violations

- JS-005: Add initialization guards to email-templates.js (admin/vendor)
- JS-006: Add try/catch error handling to content-pages.js init
- SVC-006: Move db.commit() from services to endpoints for proper
  transaction control in email_template_service and vendor_team_service

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

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

app/api/v1/admin/email_templates.py

@@ -180,6 +180,7 @@ def update_template(
         body_html=template_data.body_html,
         body_text=template_data.body_text,
     )
+    db.commit()
 
     return {"message": "Template updated successfully"}