[chore] add branch-4.1 thirdparty automation

[suxiaogang223]

Summary

Add a branch-specific thirdparty automation workflow for Apache Doris branch-4.1.

The workflow follows the existing 4.0 release pipeline and:

• watches apache/doris:branch-4.1 for changes under thirdparty/;
• publishes source and prebuilt archives under automation-4.1;
• builds Linux x86_64 and macOS arm64 artifacts;
• refreshes the 4.1 build environment Docker images.

Motivation

Related Doris PR: apache/doris#67378

The Doris PR removes the paimon-cpp source/build/link dependency while retaining compatibility with existing prebuilts. The current doris-thirdparty automation tracks Doris master, and there is no branch-4.1-specific publisher. After apache/doris#67378 is merged, this workflow can publish clean 4.1 prebuilts that no longer contain paimon-cpp libraries.

The historical paimon-cpp branch and tag remain untouched for older Doris releases.

Validation

• Parsed the workflow as YAML.
• Verified all Doris refs, release tags, download URLs, and Docker tags use 4.1.
• Compared the workflow mechanically with the existing 4.0 pipeline, with only the intended 4.1 substitutions.
• git diff --check passes.

Rollout

Merge or manually trigger this workflow after apache/doris#67378 lands on branch-4.1, so the first published 4.1 prebuilt is built from the paimon-cpp-free thirdparty definition.

[suxiaogang223]

Closing this draft because branch-4.1 shares the master thirdparty automation assets; a separate automation-4.1 workflow is not appropriate.