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-retrospective/SKILL.md

@@ -1,6 +0,0 @@
----
-name: bmad-retrospective
-description: 'Post-epic review to extract lessons and assess success. Use when the user says "run a retrospective" or "lets retro the epic [epic]"'
----
-
-Follow the instructions in ./workflow.md.