New 9P file s/{id}/react: write an emoji to record a reaction to the
most recent assistant response. The reaction is passive feedback —
no model turn is triggered.
The system prompt now documents how agents should interpret emoji
reactions (positive/negative/confused) and silently adjust behavior.
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