feat: add pinch-to-zoom support to editor

[gahanad]

Description

Adds pinch-to-zoom support to the editor to make editing more convenient on mobile devices.

Users can adjust the editor's font size using a two-finger pinch gesture, improving readability and usability on smaller screens.

Changes Made

• Added a pinch-to-zoom extension for the editor.
• Dynamically adjusts the editor font size based on the pinch gesture.
• Enforces minimum and maximum font-size limits.
• Saves the updated font size setting when the gesture ends.
• Cleans up touch event listeners when the extension is destroyed.
• Added unit tests covering pinch-zoom behavior and font-size calculations.

Testing

• Added unit tests for pinch-zoom functionality.
• Verified the targeted unit tests pass.
• Manually tested pinch-to-zoom on an Android device.
• Verified the full test suite and CI checks.

Related Issue

Closes #2426

[greptile-apps]

Confidence Score: 5/5

[Medium impact] The PR appears safe to merge; the line-number preview issue is fixed and no new actionable defects were found.

Summary

Adds two-finger pinch-to-zoom to the main editor, with size limits and one settings update when the gesture ends.

• The latest revision moves the preview to the editor root so code and line numbers zoom together.
• It updates the gesture tests to check the root.
• The numbered previous finding is fixed. No new actionable issues were found.

_{Reviews (4) · Last reviewed commit: "fix: address pinch-to-zoom review feedba..." · Reviewed by Greptile}

[gahanad]

@greptile

[gahanad]

@greptile

[gahanad]

@greptile