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-prfaq/bmad-manifest.json

@@ -1,16 +0,0 @@
-{
-  "module-code": "bmm",
-  "capabilities": [
-    {
-      "name": "working-backwards",
-      "menu-code": "WB",
-      "description": "Produces battle-tested PRFAQ document and optional LLM distillate for PRD input.",
-      "supports-headless": true,
-      "phase-name": "1-analysis",
-      "after": ["brainstorming", "perform-research"],
-      "before": ["create-prd"],
-      "is-required": false,
-      "output-location": "{planning_artifacts}"
-    }
-  ]
-}