master: update TiCDC Debezium DDL, WATERMARK support

[Copilot]

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What is changed, added or deleted? (Required)

Note

The changes to release-8.5 are made in #23524.

The TiCDC Debezium doc incorrectly stated that DDL and WATERMARK events are supported starting in v9.0.0. This update replaces that version claim with an architecture-based reference that matches actual product behavior.

• Doc correction

  • Update /ticdc/ticdc-debezium.md to remove the incorrect v9.0.0 statement.
  • State that DDL and WATERMARK events are supported in the TiCDC new architecture.

• Cross-reference cleanup

  • Link the Debezium doc directly to /ticdc/ticdc-architecture.md so the support boundary is defined by architecture, not by an incorrect version marker.

In the [TiCDC new architecture](/ticdc/ticdc-architecture.md), TiCDC supports DDL events and WATERMARK events.

Which TiDB version(s) do your changes apply to? (Required)

Tips for choosing the affected version(s):

By default, CHOOSE MASTER ONLY so your changes will be applied to the next TiDB major or minor releases. If your PR involves a product feature behavior change or a compatibility change, CHOOSE THE AFFECTED RELEASE BRANCH(ES) AND MASTER.

For details, see tips for choosing the affected versions.

• master (the latest development version)
• v9.0 (TiDB 9.0 versions)
• v8.5 (TiDB 8.5 versions)
• v8.1 (TiDB 8.1 versions)
• v7.5 (TiDB 7.5 versions)
• v7.1 (TiDB 7.1 versions)
• v6.5 (TiDB 6.5 versions)

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

• This PR is translated from:
• Other reference link(s):
  • /ticdc/ticdc-debezium.md
  • /ticdc/ticdc-architecture.md
  • https://github.com/pingcap/ticdc/blob/v8.5.4-release.1/pkg/sink/codec/debezium/encoder.go#L37
  • ticdc: update ticdc-debezium.md #19544

AI agent involvement

• The changes in this PR were primarily made by an AI agent on behalf of the PR author.

Do your changes match any of the following descriptions?

• Delete files
• Change aliases
• Need modification after applied to another branch
• Might cause conflicts after applied to another branch

• Fixes TiCDC Debezium Protocol wrongly claimed DDL/WATERMARK event is supported since v9.0.0 (it is supported since v8.5.4-release.1) #23469

[ti-chi-bot]

Hi @copilot. Thanks for your PR.

I'm waiting for a pingcap member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[lilin90]

/ok-to-test

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2026-08-13 09:10:48.379117347 +0000 UTC m=+3296834.415212403: ☑️ agreed by lilin90.
• 2026-08-14 07:59:25.770990424 +0000 UTC m=+3378951.807085490: ☑️ agreed by qiancai.

[ti-chi-bot]

@wk989898: adding LGTM is restricted to approvers and reviewers in OWNERS files.

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[lilin90]

/approve

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: lilin90

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