Add GitHub issue and PR templates

- Bug report: variant selector, affected area dropdown, repro steps
- Feature request: area dropdown, problem/alternatives fields
- New data source: feed type, variant target, URL, justification
- PR template: change type, affected areas, RSS allowlist reminder
- Config: disable blank issues, link to docs and discussions

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.github/pull_request_template.md

@@ -0,0 +1,36 @@
+## Summary
+
+<!-- Brief description of what this PR does -->
+
+## Type of change
+
+- [ ] Bug fix
+- [ ] New feature
+- [ ] New data source / feed
+- [ ] New map layer
+- [ ] Refactor / code cleanup
+- [ ] Documentation
+- [ ] CI / Build / Infrastructure
+
+## Affected areas
+
+- [ ] Map / Globe
+- [ ] News panels / RSS feeds
+- [ ] AI Insights / World Brief
+- [ ] Market Radar / Crypto
+- [ ] Desktop app (Tauri)
+- [ ] API endpoints (`/api/*`)
+- [ ] Config / Settings
+- [ ] Other: <!-- specify -->
+
+## Checklist
+
+- [ ] Tested on [worldmonitor.app](https://worldmonitor.app) variant
+- [ ] Tested on [tech.worldmonitor.app](https://tech.worldmonitor.app) variant (if applicable)
+- [ ] New RSS feed domains added to `api/rss-proxy.js` allowlist (if adding feeds)
+- [ ] No API keys or secrets committed
+- [ ] TypeScript compiles without errors (`npm run typecheck`)
+
+## Screenshots
+
+<!-- If applicable, add screenshots or screen recordings -->