[CI] Add Check Bypass for Docs change

[EmmonsCurse]

Motivation

Currently, multiple CI pipelines (GPU, XPU, etc.) still run fully even when only documentation files (.md, .txt, .yaml, .yml) are modified. This causes unnecessary queueing and waste of compute resources.
This PR introduces a unified, extensible bypass mechanism to allow CI to quickly succeed when appropriate, saving resources.

Modifications

Added reusable workflow: check-bypass.yml

• Supports two bypass conditions:
  1. PR contains a label skip-ci:
  2. PR changes only documentation files (.md/.txt/.yaml)
• Outputs a unified can-skip flag for use by downstream CI jobs.

Usage or Command

N/A

Accuracy Tests

N/A

Checklist

• Add at least a tag in the PR title.
  • Tag list: [[FDConfig],[APIServer],[Engine], [Scheduler], [PD Disaggregation], [Executor], [Graph Optimization], [Speculative Decoding], [RL], [Models], [Quantization], [Loader], [OP], [KVCache], [DataProcessor], [BugFix], [Docs], [CI], [Optimization], [Feature], [Benchmark], [Others], [XPU], [HPU], [GCU], [DCU], [Iluvatar], [Metax]]
  • You can add new tags based on the PR content, but the semantics must be clear.
• Format your code, run pre-commit before commit.
• Add unit tests. Please write the reason in this PR if no unit tests.
• Provide accuracy results.
• If the current PR is submitting to the release branch, make sure the PR has been submitted to the develop branch, then cherry-pick it to the release branch with the [Cherry-Pick] PR tag.

[paddle-bot]

Thanks for your contribution!

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
⚠️ Please upload report for BASE (develop@051b82b). Learn more about missing BASE report.

Additional details and impacted files

@@            Coverage Diff             @@
##             develop    #5248   +/-   ##
==========================================
  Coverage           ?   60.44%           
==========================================
  Files              ?      320           
  Lines              ?    39054           
  Branches           ?     5871           
==========================================
  Hits               ?    23608           
  Misses             ?    13578           
  Partials           ?     1868           

Flag	Coverage Δ
GPU	60.44% <ø> (?)

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