chore(github): add detailed issue & PR templates, capitalize title prefixes

Adds five new issue templates (bug_report_detailed, feature_request_detailed,
performance_regression, documentation, question) alongside the existing
short forms, plus an optional detailed PR template under
.github/PULL_REQUEST_TEMPLATE/ that contributors can opt into via the
?template=detailed.md URL. Existing templates keep their behavior; only
title prefixes and prose-paren wording were capitalized for consistency.

.github/ISSUE_TEMPLATE/question.md

@@ -0,0 +1,36 @@
+---
+name: Question / usage help
+about: Ask how to do something with Wickra. For open-ended discussion prefer GitHub Discussions.
+title: "[Question] <short description>"
+labels: ["question"]
+assignees: []
+---
+
+> [!NOTE]
+> If this is open-ended ("which indicator should I use for X?") please
+> use **Discussions** instead — issues are for actionable items.
+
+## What are you trying to do?
+
+<!-- The end goal, not the API call. -->
+
+## What have you tried?
+
+<!--
+Code, docs you've read, search terms that didn't help.
+Show that you've spent a few minutes before asking.
+-->
+
+```python
+import wickra as ta
+...
+```
+
+## What's confusing or blocking you?
+
+<!-- Specific question. "Why does X return NaN for the first N points?" beats "doesn't work". -->
+
+## Environment (Only if relevant)
+
+- Wickra version: `e.g. 0.4.2`
+- Binding: `Rust / Python / Node / Wasm`