Pass delta? to increase-rotation when interpreting a Rotate node. Common
turns by the node's angle; the event default instead sets an absolute
rotation, so a 45-degree turn followed by 90 degrees ended at 90 (F171).
The standalone async regression fails before the fix. The full frontend
suite passes 1524 tests and 8683 assertions, including generated replay,
undo checks and existing goldens without recording. Lint and format pass.
AI-assisted-by: GPT-6
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