Documents the new filesystem structure:
- session/{sid}/plan, env (session-level)
- session/{sid}/agent/{aid}/* (agent-level)
- Removed peer operations (deferred for redesign)
- All operations use ollie-9p CLI
The preamble is now composed as:
system_prompt + operational_model + environment + agent_prompts
- Embed SYSTEM_PROMPT.md, session-9p.md, session-dbus.md in the binary
- Render environment block at runtime with live cwd/platform/date values
- Inject operational model based on server mode (Enable9P/EnableDBus)
- Accept system_prompt= override in session creation and D-Bus CreateSession
- Agent configs no longer need to reference system/session prompt files