fix(story-mode): scheduled runs, work after a turn ended, and pages full of added prompts

From review round 4 (a 110 MB real session, about 23 turns, read through
all four tail steps):

- A scheduled task's run was drawn inside the /compact turn before it (96
  minutes and 237 tool calls credited to "You run /compact."): its prompt is
  a meta line, and work after an ended turn was appended to that turn. The
  scheduled prompt now starts a turn of origin `scheduled` ("A scheduled
  task starts this turn."), and work that comes more than 5 s after a turn
  ended starts a turn of its own ("Claude carries on"); a line Claude Code
  flushed a moment late still joins.
- A turn with seven prompts added mid-turn drew 14 panels (the cap is 12):
  missions were never folded. An added prompt may now fold into a montage,
  as the last resort after quiet panels and work panels, and the montage
  says so ("Claude keeps going (you add 2 things): ..."); the turn's own
  prompt and a question to you are never folded.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/types/story.ts

@@ -52,7 +52,7 @@ export type StoryPanelKind =
 export type StoryActor = 'you' | 'claude' | 'helper' | 'system';
 
 /** Who started a turn: you, a background task reporting back, another session, or a schedule/SDK. */
-export type StoryTurnOrigin = 'human' | 'task' | 'peer' | 'system';
+export type StoryTurnOrigin = 'human' | 'task' | 'peer' | 'scheduled' | 'system';
 
 /** One hunk of an edit, in the shape of Claude Code's `structuredPatch` (lines keep their ` `/`+`/`-` prefix). */
 export interface StoryHunk {