docs: add a Discord contact link to the issue template chooser

Shows a Discord button on the New Issue page so people can jump to
real-time discussion before filing. No mass backfill of existing threads.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.github/ISSUE_TEMPLATE/config.yml

@@ -3,6 +3,9 @@ contact_links:
   - name: Security policy
     url: https://github.com/Graphify-Labs/graphify/security/policy
     about: Please report vulnerabilities privately using the security policy.
+  - name: Discord community
+    url: https://discord.gg/XDnKVpzdXB
+    about: Join the Discord to ask questions and discuss ideas in real time.
   - name: 📖 Documentation
     url: https://github.com/Graphify-Labs/graphify/blob/v8/README.md
     about: Check the README and docs before opening an issue.