chore: clean up repo for public release

- Remove BMAD framework, IDE configs, dev screenshots, test files,
  internal docs, and backup files
- Rename keep-notes/ to memento-note/
- Update all references from keep-notes to memento-note
- Add Apache 2.0 license with Commons Clause (non-commercial restriction)
- Add clean .gitignore and .env.docker.example

memento-note/.dockerignore

@@ -0,0 +1,53 @@
+# Dependencies
+node_modules
+npm-debug.log
+yarn-error.log
+
+# Next.js
+.next
+out
+build
+dist
+
+# Production
+.env.local
+.env.development.local
+.env.test.local
+.env.production.local
+
+# Development files
+.git
+.gitignore
+README.md
+.eslintrc.json
+.prettierrc*
+
+# IDE
+.vscode
+.idea
+*.swp
+*.swo
+*~
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Testing
+coverage
+.nyc_output
+playwright-report
+test-results
+
+# Misc
+.turbo
+*.log
+
+# BMAD output (not needed in container)
+_bmad-output
+
+# Docker files
+Dockerfile
+.dockerignore
+docker-compose.yml
+deploy.sh