feat(headless): implement useTokenSelector hook

[truongnat]

Implemented useTokenSelector in the headless package to selectively subscribe to theme tokens, resolving task T-13 from IMPROVEMENT_PLAN.md.

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PR created automatically by Jules for task 8426291485733469266 started by @truongnat

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🎯 This PR implements a new useTokenSelector hook in the headless package that allows components to selectively subscribe to specific theme tokens, preventing unnecessary re-renders when unrelated theme properties change. The hook uses a selector pattern similar to Redux's useSelector to optimize performance in theme-dependent components.

🔍 Detailed Analysis

Key Changes

• Core Hook Implementation: Added useTokenSelector<T>(selector: (tokens: SemanticTokens) => T): T function in packages/headless/src/theme.tsx with memoization using useMemo
• Public API Export: Exported the new hook from packages/headless/src/index.ts to make it available to consumers
• Documentation Updates: Updated GitNexus configuration files and project metadata to reflect current codebase state (project renamed from "rnui" to "app")
• Dependency Management: Minor lockfile updates removing unused configuration version

Technical Implementation

sequenceDiagram
    participant Component
    participant useTokenSelector
    participant useTokens
    participant ThemeProvider
    
    Component->>useTokenSelector: selector function
    useTokenSelector->>useTokens: get all tokens
    useTokens->>ThemeProvider: retrieve SemanticTokens
    ThemeProvider-->>useTokens: return tokens
    useTokens-->>useTokenSelector: return tokens
    useTokenSelector->>useTokenSelector: useMemo(selector(tokens))
    useTokenSelector-->>Component: return selected value
    
    Note over useTokenSelector: Only re-renders when selected tokens change

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Impact

• Performance Optimization: Components using useTokenSelector will only re-render when their specific selected tokens change, not on every theme update
• Developer Experience: Provides a familiar selector pattern for theme token consumption, similar to state management libraries
• Backward Compatibility: Existing useTokens() usage remains unchanged, making this a non-breaking addition to the API
• Memory Efficiency: Memoization prevents unnecessary selector function executions and reduces computational overhead

Created with Palmier

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Summary by cubic

Adds useTokenSelector to the headless theme API so components can subscribe to specific token slices and avoid unnecessary re-renders.

• New Features
  • Introduces useTokenSelector<T>(selector) to derive values from SemanticTokens and memoize the result; exported via packages/headless/src/index.ts.
  • Use it instead of useTokens when you only need a subset of tokens; no breaking changes.

^{Written for commit c38d877. Summary will update on new commits.}

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Project	Deployment	Actions	Updated (UTC)
rnui-docs	Ready	Preview, Comment	Apr 7, 2026 0:29am

[cubic-dev-ai]

No issues found across 11 files