Video export loads page after page into one offscreen capture. That
capture ran the editor's strategy provider, which treats each change to
the page's agents, drawings and the rest as an edit: from the second
page on, a local strategy was marked unsaved, and if rendering ran past
the 15-second autosave delay, the autosave wrote the page being rendered
over the page open in the editor.

Reproduced on a release build of main: a 20-page Max export of a local
strategy replaced page 1 (58 agents) with page 20's content on disk.
4.6.3 does the same, and earlier, since its capture opens the strategy
before loading the first page. Cloud strategies were not affected: the
capture's copy can't edit them, so nothing was queued.

The capture container now holds the strategy in a provider without that
edit tracking, as it already did for auth. A test loads two pages into a
capture and finds the strategy never marked unsaved; it fails without
the fix.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>