fix(story-mode): a push in its own command is not a commit

From review round 6: commit, then push as a second command (the most
common way to ship) drew as "Claude saves the work in 2 commits and
uploads it." for one commit, and the commit's message was dropped. A
command's `commits` was only recorded above one, and the save panel then
counted every save command as one. It is now recorded whenever a command
commits and is the only thing counted: "Claude saves the work and uploads
it: "feat: add mode()"." A push of earlier commits reads "Claude uploads
the work."

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

test/fixtures/story-corpus/question-tests-first-push.expected.json

@@ -91,7 +91,7 @@
       {
         "kind": "save",
         "ok": true,
-        "story": "Claude saves the work in 2 commits and uploads it, but a step after that fails.",
+        "story": "Claude saves the work and uploads it, but a step after that fails.",
         "director": "git commit -q -F - · git push -u origin main · 1 error",
         "balloon": null,
         "tests": null,