feat: persist orchestrator sessions + user service + docs update

- Orchestrator now saves turns to session store so history survives page refresh
- UI session_id updated from job result; history controls attached to agent turns
- Cortex migrated from system service to systemd user service (no more sudo)
- Update README.md and CLAUDE.md with correct service commands

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

CLAUDE.md

@@ -78,7 +78,7 @@ Cortex_and_Inara_dev/
 docker compose up -d
 
 # Restart service (after any Python change)
-sudo systemctl restart cortex
+systemctl --user restart cortex
 
 # Syntax check a file before restarting
 python3 -m py_compile cortex/<file>.py
@@ -92,7 +92,7 @@ done
 cd cortex && .venv/bin/pip install -r requirements.txt
 
 # Logs
-journalctl -u cortex -f
+journalctl --user -u cortex -f
 
 # Web UI (local)
 http://localhost:8000