chore: add PR templates (feature, bug fix) with issue linking and concise checklist

.github/PULL_REQUEST_TEMPLATE/bugfix.md

@@ -0,0 +1,9 @@
+Fixes #<issue-number>
+
+Summary of the fix
+- What changed and why in 1–3 sentences.
+
+Checklist
+- [ ] Linked to issue(s) above by issue number (e.g. `Closes #<issue-number>`)
+- [ ] One problem per PR (no unrelated changes)
+- [ ] Lints pass; CI green

.github/PULL_REQUEST_TEMPLATE/feature.md

@@ -0,0 +1,18 @@
+Closes #<issue-number>
+
+Summary
+
+- What and why in 1–3 sentences.
+
+Screenshots/videos (UI changes)
+
+- Add before/after images or a short clip.
+
+Checklist
+
+- [ ] Linked to issue(s) above by issue number (e.g. `Closes #<issue-number>`)
+- [ ] One problem per PR (no unrelated changes)
+- [ ] Lints pass; CI green
+- [ ] Tricky parts are commented in code
+- [ ] Internationalization (see `DEVELOPMENT.md` for details)
+- [ ] Backward compatible with existing device firmware (See `DEVELOPMENT.md` for details)