br: improve visualization of BR

[Leavrth]

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What is the related PR or file link(s)?

• This PR is translated from:
• Other reference link(s): br: improve summary and progress visualization of br tidb#56612

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[qiancai]

Rest LGTM

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2025-03-14 03:24:12.411668639 +0000 UTC m=+499008.017197570: ☑️ agreed by qiancai.
• 2025-03-17 03:00:39.172484047 +0000 UTC m=+238132.856720141: ☑️ agreed by hfxsd.

[hfxsd]

/approve

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