chore(issues): point the issue chooser at this repo, not upstream Cinny

The forked-in Cinny issue setup funneled reporters to the upstream project:
- config.yml disabled blank issues and linked to cinnyapp/cinny GitHub
  Discussions
- preapproved.md was Cinny's "do not open an issue, use Discussions"
  template (Gitea has no Discussions anyway)

Replace it with a Lotus setup: enable blank issues, drop the upstream
contact link, and add Bug Report + Feature Request templates. Now
/issues/new/choose offers Lotus templates and files against this repo.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.github/ISSUE_TEMPLATE/feature_request.md

@@ -0,0 +1,15 @@
+---
+name: Feature Request
+about: Suggest an idea or improvement for Lotus Chat
+title: ''
+labels: enhancement
+---
+
+**What would you like?**
+A clear and concise description of the feature or change.
+
+**Why / use case**
+What problem does it solve, or what does it make better?
+
+**Alternatives considered**
+Any workarounds or other approaches you've thought about.