fix: correct Claude Code plugin URL and disable blank issues

- Fix vibecoding docs: plugin uses openmemory.ai, not app.openmemory.dev
  (they are separate products that don't communicate)
- Disable blank issue template in GitHub issue config

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.github/ISSUE_TEMPLATE/config.yml

@@ -1,4 +1,4 @@
-blank_issues_enabled: true
+blank_issues_enabled: false
 contact_links:
   - name: Discord Community
     url: https://discord.gg/6PzXDgEjG5