Create question or discussion issue template

Added a template for questions and discussions to guide users towards using GitHub Discussions.

.github/ISSUE_TEMPLATE/question-or-discussion.md

@@ -0,0 +1,18 @@
+---
+name: Question or Open Discussion
+description: Have a question or want to discuss something? → Use Discussions instead!
+title: "[Discussion] "
+labels: ["question"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Thanks for wanting to start a conversation!
+
+        For questions, brainstorming, or non-actionable discussion, please use **GitHub Discussions** instead:
+
+        👉 https://github.com/jacob-kraniak/the-book-of-secret-knowledge/discussions/new
+
+        This helps keep Issues focused on actionable work (bugs, features, migrations).
+
+        You can close this issue now — or comment if you really prefer it here.