Subagent completions already got this: the model receives the full
`[ASYNC DELEGATION …]` text while the CLI/TUI/Desktop paint a one-line
"Subagent Task Completed: <goal>" event. Background-process completions
(`terminal(background=True, notify=True)`) still echoed the entire
`[IMPORTANT: Background process proc_… completed normally (exit code 0).
Command: … Output: …]` block as if the user had typed it.
Generalise the delegation mechanism: `TimelineNotification` (formerly
`SubagentNotification`) carries `display_kind` + `display_text`;
`ProcessNotificationBatch` renders a `process_complete` one with a
`process_completion_display_text` title ("Background Process Finished:
<cmd>", "Background Process Failed (exit 1): <cmd>", "N Background
Processes Finished"). The TUI gateway stamps the same kind/metadata on
the synthesized turn and emits the title on `status.update`; Ink and
Desktop project `process_complete` rows as timeline events (Desktop keeps
the raw output behind the existing expandable async-result row). Model
content is byte-identical to before.
teknium1