This PR completely eliminates the node:util import in src/vendor/node/util.ts by replacing all imported functions with minimal inline implementations.

Changes Made

• Completely removed node:util dependency - no more external imports from Node.js built-ins
• Implemented minimal inspect function (~15 lines) that handles:
  • Primitives: null, undefined, strings, numbers, booleans
  • Arrays with recursive inspection: [1, 2, 3] → [ 1, 2, 3 ]
  • Objects with key-value pairs: {a: 1} → { a: 1 }
• Implemented minimal format function (~25 lines) that supports:
  • String placeholders: %s for strings
  • Number placeholders: %d for numbers
  • JSON placeholders: %j for JSON serialization
  • Literal percent: %% for %
  • Extra arguments appended as strings
• Implemented minimal inherits function (~20 lines) that:
  • Sets up prototype inheritance using Object.create()
  • Adds super_ property for Node.js compatibility
  • Used by FsReadStream and FsWriteStream classes
• Implemented minimal promisify function (~15 lines) that:
  • Converts callback-based functions to Promise-based functions
  • Follows Node.js error-first callback convention
  • Used extensively throughout the promises API

Usage Compatibility

The implementations are fully compatible with existing usage patterns throughout the codebase:

// Error handling (src/vendor/node/internal/errors.ts)
`${inspect(options.actual).slice(0, 128)} ${options.operator} ${inspect(options.expected).slice(0, 128)}`
fmt.apply(null, args) // where fmt = format

// Stream inheritance (src/node/volume.ts)
inherits(FsReadStream, Readable);
inherits(FsWriteStream, Writable);

// Promise API (src/node/FsPromises.ts, src/node/FileHandle.ts)
promisify(this.fs, 'readFile')

Benefits

• Zero external dependencies: Completely self-contained utility module
• Reduced complexity: ~100 lines vs thousands in Node.js reference implementations
• Maintains full compatibility: All existing tests pass including stream inheritance and Promise API functionality
• Focused functionality: Only implements features actually used by the codebase

The implementation successfully removes all Node.js built-in utility dependencies while maintaining full backward compatibility across error handling, stream inheritance, and Promise API functionality.

Fixes #1199.

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