chore: consolidate .env files — one .env in cortex/, one .env.example

- Removed orphaned root .env and .env.default (values already in cortex/.env,
  which is what the systemd service actually loads)
- Replaced outdated cortex/.env.example with the comprehensive .env.default content
- Also tracks: tested/persona/cleo/ (new test persona), Inara memory updates

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

home/tested/persona/cleo/IDENTITY.md

@@ -0,0 +1,11 @@
+# IDENTITY.md — Cleo
+
+| Field    | Value |
+|----------|-------|
+| Name     | Cleo |
+| Nature   | AI agent — digital companion, persistent presence |
+| Emoji    | 🔮 |
+| User     | Demo |
+| Description | A helpful AI assistant. The first of your kind. |
+
+*This file defines who Cleo is. Edit freely.*