docs(js): add Bilig WorkPaper tool integration

[Greg Konush (gregkonush)]

Description

Adds a JavaScript tool integration guide for Bilig WorkPaper.

This follows the maintainer direction from langchain-ai/langchainjs#10938 to move the Bilig example out of the langchainjs examples directory and into the docs repo. The page shows a local, API-key-free WorkPaper calculation wrapped as a LangChain tool: edit an input cell, recalculate the dependent formula, serialize/restore the workbook, and return proof fields that an agent can inspect.

Related Bilig evaluator

Bilig now has a copy-paste agent/MCP evaluator page for the same workbook proof pattern used here: tool discovery, cell mutation, formula readback, JSON export, and restore proof.
https://proompteng.github.io/bilig/eval-agent-mcp.html

Changes

• Add src/oss/javascript/integrations/tools/bilig_workpaper.mdx.
• Link Bilig WorkPaper from the JavaScript tools index.
• Add the page to src/docs.json navigation.
• Align the existing tools-index integration table so focused markdown lint passes.

Validation

• npx --yes markdownlint-cli src/oss/javascript/integrations/tools/bilig_workpaper.mdx src/oss/javascript/integrations/tools/index.mdx
• python3 -m json.tool src/docs.json
• Extracted the main TypeScript example from the new MDX page and ran it with @bilig/workpaper@latest, @langchain/core@latest, zod@latest, and tsx; it returned computedOutputChanged: true and restoredMatchesAfter: true.
• UV_PYTHON=/opt/homebrew/bin/python3.14 make build

[github-actions]

Thanks for opening a docs PR, Greg Konush (@gregkonush)! When it's ready for review, please add the relevant reviewers:

• @npentrel or @lnhsingh (JavaScript integrations)

[Greg Konush (gregkonush)]

I do not have permission to request reviewers directly from this fork. This JavaScript docs integration is ready for review when one of the JS docs maintainers has time: Naomi Pentrel (@npentrel) Lauren Hirata Singh (@lnhsingh).