[navigation menu] Add generic Value typing

[atomiks]

Summary

Adds generic value typing to NavigationMenu.Root so value, defaultValue, and onValueChange infer the selected item type the same way Accordion already does. This keeps the existing permissive default when no generic is provided while improving type safety for controlled and uncontrolled usage.

Changes

• Add a NavigationMenuValue<Value> alias and thread the generic through NavigationMenu.Root props and namespace exports.
• Update the root context typing so the internal setter matches the public generic value shape.
• Add compile-time spec coverage for inference, explicit generics, nullable values, and the backward-compatible any default.
• Regenerate the Navigation Menu API reference metadata.

[atomiks]

Codex Review

Overview

This patch adds generic value typing to NavigationMenu.Root so value, defaultValue, and onValueChange infer the selected item type instead of defaulting to any. It also adds compile-time coverage and updates the generated API reference so the docs show the simpler Value | null form.

Findings (None)

No blocking issues found in this patch.

Confidence: 4/5

High confidence based on a full review of the branch diff, a second-pass sweep for render correctness, accessibility impact, API and state design, maintainability, performance risk, and test coverage, plus validation with pnpm typescript, pnpm test:jsdom NavigationMenuRoot --no-watch, pnpm docs:api, pnpm eslint, pnpm stylelint, and pnpm markdownlint.

Notes

• The runtime behavior is unchanged; the patch is limited to public typing, compile-time assertions, internal context typing, and generated API metadata.
• I did not run a benchmark because the change does not alter hot-path runtime logic, layout work, or bundle size.

[pkg-pr-new]

• base-ui-tanstack-start

• vite-css-base-ui-example

  pnpm add https://pkg.pr.new/mui/base-ui/@base-ui/react@4328
  

  pnpm add https://pkg.pr.new/mui/base-ui/@base-ui/utils@4328
  

commit: af9ac6a

[mui-bot]

Bundle size report

Bundle	Parsed size	Gzip size
@base-ui/react	0B(0.00%)	0B(0.00%)

Details of bundle changes

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