The D-Bus method was missing the remote parameter that session.Manager
already supports. Add it as the 6th arg after system_prompt so frontends
can create remote execution sessions via D-Bus.
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