Remove local to global scroll resync above some threshold

[severo]

Before: we would switch to global scrolling after scrolling 500 rows locally.
After: we always stay in local scroll mode, when scrolling row by row.

Screencast.From.2026-02-23.14-45-35.mp4

fixes #435

[Copilot]

Pull request overview

This PR removes the accumulated localOffset threshold check from the dual-mode virtual scrolling implementation, allowing continuous local scrolling without forced resynchronization to global scroll mode after 500 rows. This change addresses issue #435, which identified that the previous behavior could theoretically make some rows inaccessible in datasets with more than 4 billion rows.

Changes:

• Removed the accumulated localOffset check from canBeLocalScroll() function, keeping only the per-delta size check
• Updated test descriptions and expectations to reflect the new behavior where local scrolling continues regardless of accumulated offset
• Simplified function signatures by removing the now-unused localOffset parameter from the scroll eligibility check

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/helpers/scroll.ts	Removed accumulated localOffset check from canBeLocalScroll(), allowing indefinite local scrolling when individual scroll deltas remain small
test/helpers/scroll.test.ts	Updated test descriptions and expectations to validate that local scrolling continues even when accumulated localOffset exceeds the threshold

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[severo]

wdyt @platypii?

[severo]

another gentle ping @platypii @bleakley