ci: add GitHub workflows and issue templates

Problem: need CI for tests, quality checks, luarocks publishing,
and structured issue/discussion templates.

Solution: add test, quality, and luarocks workflows mirroring
diffs.nvim conventions. Add bug report, feature request, and
Q&A templates.

.github/ISSUE_TEMPLATE/feature_request.yaml

@@ -0,0 +1,30 @@
+name: Feature Request
+description: Suggest a feature
+title: 'feat: '
+labels: [enhancement]
+body:
+  - type: checkboxes
+    attributes:
+      label: Prerequisites
+      options:
+        - label:
+            I have searched [existing
+            issues](https://github.com/barrettruth/todo.nvim/issues)
+          required: true
+
+  - type: textarea
+    attributes:
+      label: Problem
+      description: What problem does this solve?
+    validations:
+      required: true
+
+  - type: textarea
+    attributes:
+      label: Proposed solution
+    validations:
+      required: true
+
+  - type: textarea
+    attributes:
+      label: Alternatives considered