chore(github): overhaul issue and PR templates

Bug, feature, and question templates now collect the triage signal the
maintainers usually have to ask for (install method, OS, area, reverse
proxy, logs, version). config.yml disables blank issues and points to
Wiki / existing issues / latest release from the picker.

PR template adds Summary/Why/Type/Areas/Testing/Breaking-changes
sections and a fuller checklist (build, tests, lint, typecheck, docs).
Renamed pull_request_template.yml -> .md to match GitHub's conventional
extension; the old .yml was being read as markdown anyway.

.github/ISSUE_TEMPLATE/config.yml

@@ -0,0 +1,11 @@
+blank_issues_enabled: false
+contact_links:
+  - name: 📖 Project Wiki
+    url: https://github.com/MHSanaei/3x-ui/wiki
+    about: Setup, install, configuration, and "how do I…" guides live here. Please check before opening a question.
+  - name: 🔍 Search existing issues
+    url: https://github.com/MHSanaei/3x-ui/issues?q=is%3Aissue
+    about: Your bug, feature, or question may already be tracked. Comment on the existing one rather than opening a duplicate.
+  - name: 🚀 Latest release
+    url: https://github.com/MHSanaei/3x-ui/releases/latest
+    about: Reproduce on the latest version before reporting — many bugs are already fixed in the most recent release.