docs: align documentation with current implementation.

[shirley-yang-1988]

Description

Correct stale documentation content so the bilingual guides, routes, CLI reference, and examples match the current implementation.

• Repair documentation language links and sidebar/cookbook routes for GLM-5.1, GLM-5.2, and Wan2.2.
• Align the CLI reference with native configuration precedence and current defaults for max_seqs_per_batch, enable_mix_batch, and block-copy kernels.
• Update the Wan2.2 recipe to use visible-device environment selection instead of the removed --devices flag.
• Distinguish xLLM backend selection (setup.py --device npu) from TileLang Ascend architecture selection (compile-kernels --device a2|a3).
• Point generative-recommendation documentation to the current C API usage example.

Related Issues

None.

Change Type

• Documentation

Pull Request Checklist

PR Title and Commit Messages

• The PR title and each commit message follow the xLLM commit format: <type>: <subject>.

Pre-commit Checks

• I have installed pre-commit by running pip install pre-commit or an equivalent command.
• I have installed the hooks with pre-commit install.
• I have run pre-commit run --all-files and fixed any reported issues.

Self Review

• I have self-reviewed the documentation changes against their source definitions and referenced routes.
• I have rebased this PR onto the latest main branch.

Build and Test Coverage

• Tests have been added or updated as needed.
• CUDA: python setup.py build test has passed on a CUDA machine.
• NPU: python setup.py build test has passed on an NPU machine.
• MLU: python setup.py build test has passed on an MLU machine.

Validation

• npm --prefix docs run check
• npm --prefix docs run build
• Link, sidebar-route, localization-parity, and Wan2.2 shell-syntax audits
• pre-commit run --from-ref origin/main --to-ref HEAD

No accelerator build or test was run for this documentation-only change.

Reviewer Notes

The native configuration precedence wording is intentionally scoped to native C++ configuration; it does not generalize launcher-owned settings such as service topology.