fix: maintain integer column widths and allocate remainder to the last auto-fit column

[Alexzjt]

👀 PR includes

🐛 Bugfix

• Solve the issue and close 🐛明细表右侧存在多余的空白 #3348

🔧 Chore

• Test case

📝 Description

Maintain integer column widths using round(), and compensate for any remainder pixels by allocating them to the last auto-fit column.

Only columns that actually use auto-fit widths are eligible for this compensation (excluding row index columns, manually resized columns, and columns with a custom colCell.width). Therefore, scenarios involving custom column widths remain completely unaffected.

"Distribute the remainder pixels lost during floor() calculation to a specific column (typically the last one), ensuring that the total column width exactly matches the available width."

保持 round() 整数列宽，余数补给最后一个自适应列
只有实际使用自适应宽度的列才参与补偿（排除序号列、拖拽调整过的列、有自定义 colCell.width 的列），所以自定义列宽场景不受影响。
"将 floor() 丢失的余数像素分配到某一列（通常最后一列），确保总列宽恰好等于可用宽度"

🖼️ Screenshot

Before	After
❌	✅

⚠️ Breaking Changes

• Yes
• No

🔍 Self-Check before the merge

• Add or update relevant docs.
• Add or update relevant demos.
• Add or update test case.
• Add or update relevant TypeScript definitions.

[gemini-code-assist]

Code Review

This pull request simplifies the column width calculation in table-facet.ts by removing a redundant round() call on adaptiveColWidth, as it is already floored in getAdaptiveColWidth. There are no review comments to address, and the change looks correct.

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[github-actions]

Size Change: +157 B (+0.02%)

Total Size: 745 kB

📦 View Changed

Filename	Size	Change
packages/s2-core/dist/s2.min.js	312 kB	+157 B (+0.05%)

ℹ️ View Unchanged

Filename	Size
packages/s2-core/dist/s2-extends.min.js	209 kB
packages/s2-core/dist/s2.min.css	583 B
packages/s2-react-components/dist/s2-react-components.min.css	2.55 kB
packages/s2-react-components/dist/s2-react-components.min.js	123 kB
packages/s2-react/dist/s2-react.min.css	1.3 kB
packages/s2-react/dist/s2-react.min.js	38.5 kB
packages/s2-vue/dist/s2-vue.min.css	3.8 kB
packages/s2-vue/dist/s2-vue.min.js	54.2 kB

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[github-actions]

🎉 This PR is included in version @antv/s2-v2.7.2-alpha.1 🎉

The release is available on:

• npm package (@alpha dist-tag)
• GitHub release

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