Refactor: Encapsulate document screen size update into a function

[noborus]

Improved code clarity and maintainability by refactoring the document screen size update logic into a dedicated function.

[Copilot]

Pull request overview

This PR refactors the document screen size update logic by extracting it into a dedicated updateDocumentSize() function, improving code maintainability and reducing duplication. The refactoring also includes improved variable naming in the status line drawing code.

Changes:

• Extracted document size calculation into updateDocumentSize() function
• Updated tests to set screen dimensions via root.scr.vWidth/vHeight instead of directly setting document width
• Improved variable naming in drawRightStatus() for better clarity

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
oviewer/prepare_draw.go	Added updateDocumentSize() function to encapsulate document size calculations; updated prepareScreen() and prepareDraw() to use the new function; changed minimum screen size from 1 to 2
oviewer/status_line.go	Renamed variables str to numStr and width to numWidth for improved clarity
oviewer/prepare_draw_test.go	Updated test setup to set root.scr.vWidth/vHeight before calling prepareScreen()
oviewer/move_leftright_test.go	Updated multiple tests to set root.scr.vWidth instead of directly setting m.width

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[Copilot]

The minimum screen size has been changed from 1 to 2. This change should be verified to ensure it doesn't cause issues with edge cases or existing behavior. Additionally, this appears to be an unrelated change that should ideally be in a separate commit or PR focused on changing minimum screen size requirements, rather than in a refactoring PR.

Suggested change

	root.scr.vHeight = max(root.scr.vHeight, 2)
	root.scr.vHeight = max(root.scr.vHeight, 1)