docs: mark LingTai collaboration as historical

[wchwawa]

Related Issue

Closes #519

Summary

Mark the LingTai collaboration as historical and remove it as a default integration target. Keep historical announcements and qualification artifacts with their original context.

Scope

• Documentation and review guidance only; no runtime change.
• CLI-first integration order remains unchanged.

Change Size And Review

GitHub reports 28 additions + 28 deletions = 56 changed lines. Remote product checks passed at eef8617.

Code Contract (Code Changes Only)

• Not applicable; documentation only.

Claims and Evidence

• Current collaboration direction is separated from historical records.

Validation

Markdown links and git diff --check passed locally. Remote CI passed: Rust and recovery gates, manylinux wheel and SDK, amd64/arm64 image build, DCO and change-size governance. No new runtime qualification is claimed for this documentation-only change.

Contributor Sign-off

• Every commit includes the maintainer's DCO sign-off.