docs: add API Route to Python provider listings

[DennyHo0917]

Overview

Add API Route to the Python provider directory and chat model comparison table. API Route offers an OpenAI-compatible endpoint that can be used with the existing ChatOpenAI client via base_url; it does not have a separate LangChain package. The external link points to the API Route product documentation.

Capability cells remain blank because I have not verified streaming, tool calling, structured output, or multimodal behavior through LangChain for a specific model. This follows the recently merged external-provider listing pattern in #6168 while avoiding unverified feature claims.

Type of change

Type: Update existing documentation

Related issues/PRs

• GitHub issue: None
• Feature PR: None; existing OpenAI-compatible client

Checklist

• I have read the contributing guidelines, including the language policy.
• I have tested my changes locally using docs dev (sparse checkout; not run).
• All code examples have been tested and work correctly (no code examples added).
• I have used root relative paths for internal links (no internal links added).
• I have updated navigation in src/docs.json if needed (no new page).

Additional notes

• Vale 3.17.1 on both changed MDX files: 0 errors, 0 warnings.
• --check-docs-urls: passed.
• The table row matches _render_row output for this external entry.
• git diff --check: passed.
• An AI coding agent helped prepare this PR.

[github-actions]

Thanks for opening a docs PR, DennyHo0917! When it's ready for review, please add the relevant reviewers:

• @mdrxy (Python integrations)

[langchain-oss-automated-triage]

Thanks for contributing a new integration docs page, DennyHo0917!

New integration listings should be filed as an Integration listing issue rather than a manual PR. Automation opens a review PR from the form fields. See the integration submission process.

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