[FLINK-40598][docs] Synchronize Chinese Elastic Scaling documentation

[Jackeyzhe]

What is the purpose of the change

The Chinese elastic scaling page still contains substantial untranslated
English content and is missing several updates from the English page. This
change completes the translation under FLINK-40598.

Brief change log

• Translate the introduction, Adaptive Scheduler, Externalized Declarative
  Resource Management, usage, limitations, and Rescale History sections.
• Synchronize the missing scaling interval guidance and the TaskManager
  shutdown qualification in the existing Reactive Mode translation.
• Preserve stable section anchors and fix links whose targets differ in the
  Chinese documentation.
• Refresh the Kubernetes Operator autoscaler link in both English and Chinese.
• Restore the stable flink-configuration-file anchor in the Chinese
  configuration page.

Verifying this change

This documentation-only change was verified as follows:

• Built the complete documentation site with Hugo extended 0.124.1.
• Reapplied the final patch without conflicts to upstream master
  0bc5d308ba8 and rebuilt 506 English and 505 Chinese pages.
• Inspected the rendered Chinese page, including the table of contents, hints,
  nested lists, code blocks, and images.
• Verified that the English and Chinese Elastic Scaling pages render the stable
  Operator autoscaler URL and that the URL returns HTTP 200.
• Verified that the Chinese configuration page renders both
  flink-configuration-file and its generated Chinese heading anchor.
• Verified unchanged frontmatter/license and code blocks, matching Hugo
  shortcodes, preserved Web UI labels, valid page-local links and image files,
  and no untranslated prose paragraphs.
• Ran git diff --check.

Does this pull request potentially affect one of the following parts:

• Dependencies: no
• Public API: no
• Serializers: no
• Runtime per-record code paths: no
• Deployment or recovery behavior: no; documentation text only
• S3 file system connector: no

Documentation

• Does this pull request introduce a new feature? no

Was generative AI tooling used to co-author this PR?

• [] Yes

Generated-by:

[flinkbot]

CI report:

• 1196772 Azure: SUCCESS

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