* Use bg-primary-darkest for stage background contrast

MainSection now falls back to bg-primary-darkest (shade 950) instead
of bg-primary-very-dark (shade 900), providing visual contrast between
the stage background and sidebar/panel layers.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* Bump version to 1.0.14

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

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Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>