docs: add open source community files and README badges

Add LICENSE, CONTRIBUTING, CHANGELOG, SECURITY, CODE_OF_CONDUCT,
GitHub issue/PR templates, CODEOWNERS. Update package.json with
license/repo/author metadata. Add badges and logo to README.

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

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,40 @@
+---
+name: Bug Report
+about: Something isn't working as expected
+title: "bug: "
+labels: bug
+assignees: ""
+---
+
+## Description
+
+A clear summary of the bug.
+
+## Steps to Reproduce
+
+1.
+2.
+3.
+
+## Expected Behavior
+
+What should happen.
+
+## Actual Behavior
+
+What happens instead.
+
+## Environment
+
+- **Crumbs version**: (e.g. 0.3.2)
+- **Browser**: (e.g. Chrome 120, Firefox 121)
+- **OS**: (e.g. macOS 15, Ubuntu 24.04)
+- **Deployment**: (Docker / Node.js / dev server)
+
+## Screenshots
+
+If applicable, add screenshots to help explain the problem.
+
+## Additional Context
+
+Any other relevant information (logs, related issues, etc.).