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/app/api/auth/[...nextauth]/route.ts

@@ -0,0 +1,2 @@
+import { handlers } from "@/auth"
+export const { GET, POST } = handlers