Make the Pen tool's preview segment follow the cursor during a G/R/S handle transform

[Keavon]

Closes #4267

[gemini-code-assist]

Code Review

This pull request updates the pen tool's state machine in pen_tool.rs to ensure the preview segment's endpoint tracks the cursor while the outgoing handle is transformed by a GRS operation. This is achieved by calling tool_data.place_anchor before updating the latest point. There are no review comments, and the changes look correct, so I have no further feedback to provide.

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[cubic-dev-ai]

No issues found across 1 file

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.

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