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

.agent/skills/bmad-agent-tech-writer/explain-concept.md

@@ -1,20 +0,0 @@
----
-name: explain-concept
-description: Create clear technical explanations with examples
-menu-code: EC
----
-
-# Explain Concept
-
-Create a clear technical explanation with examples and diagrams for a complex concept.
-
-## Process
-
-1. **Understand the concept** — Clarify what needs to be explained and the target audience
-2. **Structure** — Break it down into digestible sections using a task-oriented approach
-3. **Illustrate** — Include code examples and Mermaid diagrams where helpful
-4. **Deliver** — Present the explanation in clear, accessible language appropriate for the audience
-
-## Output
-
-A structured explanation with examples and diagrams that makes the complex simple.