docs: issues on the GitHub mirror, with bug and feature forms

The README says pull requests aren't taken and points to issues on the
GitHub mirror. Issue forms for bug reports and feature requests set the
bug and enhancement labels; blank issues are off.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

.github/ISSUE_TEMPLATE/feature.yml

@@ -0,0 +1,20 @@
+name: Feature request
+description: An idea for lazysecrets, or something that could work better.
+labels: [enhancement]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        lazysecrets stays focused on finding, reading and sharing secrets, so not every idea will make it in, but they're all read.
+  - type: textarea
+    id: problem
+    attributes:
+      label: What you're trying to do
+      description: The problem or the situation, more than the solution.
+    validations:
+      required: true
+  - type: textarea
+    id: idea
+    attributes:
+      label: Your idea
+      description: How you'd like it to work, if you have one in mind.