fix(story-mode): commits in montages, lint verdicts, and a page that holds still

From review round 2 (a long turn, and a prompt added mid-turn):

- Commits fold last and a montage names them ("saves the work in 3
  commits"); a save counts its commits ("saves the work in 6 commits").
  Before, all three commits of a 16-step turn vanished into montages that
  read "runs 2 commands".
- Folding a full page starts at the oldest pair and grows a montage already
  there, and never takes the newest panel while another choice exists: a
  live page no longer reshuffles panels the reader is watching.
- A check whose output reports problems ("1 file would be reformatted",
  "Found 3 errors", "✖ 5 problems", `error TS…`) failed, though a trailing
  `; ls` hid the exit code: "The tests pass, but another check fails."
- Shell structure is not a command (`for x in`, `do`, `done`, `if`), so a
  `--version` probe in a loop reads as looking; `command -v` and
  `git config --get` too.
- The montage draws only the kinds of steps it folded, with a box for
  saves; the loop's arrow has a head and rests on a finished page; the
  "MISSION COMPLETE!" title has room for its tilt; drawer commands keep
  their line breaks.

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

src/types/story.ts

@@ -126,6 +126,8 @@ export interface StoryEvent {
   description?: string;
   /** A save that ships the work: `gh pr create` (`pr`) or `git push` (`push`). */
   ships?: 'pr' | 'push';
+  /** How many commits a Bash call makes (`git commit` segments). */
+  commits?: number;
   /** Who a prompt came from (a prompt added mid-turn can come from someone other than the turn's starter). */
   origin?: StoryTurnOrigin;
   output?: string;