fix: Sticky add tolerance when judging sticky state

[TinaPeach]

This pull request addresses a UI issue with the Sticky component in index.tsx by introducing a tolerance threshold to prevent jitter during iOS damping animations. The main change is to adjust the sticky position calculations to be less sensitive to minor pixel differences, which helps avoid unwanted visual shaking on iOS devices.

Sticky positioning improvements:

• Added a TOLERANCE constant to the sticky position calculations to avoid jitter caused by iOS damping animation, improving user experience on iOS devices.
• Updated the logic for determining isTopSticky and isBottomSticky to include the tolerance threshold, making sticky state transitions smoother and less prone to flickering.

[codecov]

Codecov Report

❌ Patch coverage is 71.42857% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.27%. Comparing base (62ea305) to head (4523fd8).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
packages/arcodesign/components/sticky/index.tsx	71.42%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #347      +/-   ##
==========================================
- Coverage   90.28%   90.27%   -0.01%     
==========================================
  Files         141      141              
  Lines        8498     8501       +3     
  Branches     3478     3480       +2     
==========================================
+ Hits         7672     7674       +2     
- Misses        803      804       +1     
  Partials       23       23              

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[Copilot]

Pull Request Overview

This PR fixes jitter issues in the Sticky component by adding tolerance thresholds when determining sticky states, specifically targeting iOS damping animation problems.

• Added a tolerance threshold (0.5px) to prevent jitter during iOS damping animations
• Removed unnecessary Math.round() calls from distance calculations to preserve precision
• Applied tolerance to both top and bottom sticky state calculations

---

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[Copilot]

The magic number 0.5 should be extracted to a named constant at the module level or made configurable through props. This would improve maintainability and allow fine-tuning if needed.

[Copilot]

The tolerance is being added to topOffset but subtracted from followOffset. This asymmetric application of tolerance could be confusing. Consider documenting why different directions are used or ensuring consistent application.

Suggested change

	? disFromTop <= topOffset + TOLERANCE &&
	followBottom > containerTop + followOffset - TOLERANCE
	followBottom > containerTop + followOffset + TOLERANCE

[github-actions]

✨ PR Preview Link: https://preview-347-arco-design-mobile.surge.sh

[adaex]

应该问题不大