Consistent variable style patterns

Maintain consistent patterns for variable declarations and naming conventions:

1. Use const by default for variable declarations, only use let when the variable needs to be reassigned
2. Use clear, complete words in variable names instead of abbreviations
3. For truthiness checks, prefer simple boolean conditions unless explicit null/undefined checks are required

Example:

// ❌ Inconsistent patterns
let lockFile = findRootLockFile(cwd)
const normChunkPath = '/path'
if (testWasmDir != null) {
  // ...
}

// ✅ Consistent patterns
const lockFile = findRootLockFile(cwd)
const normalizedChunkPath = '/path'
if (testWasmDir) {
  // ...
}

This promotes code readability and reduces cognitive load by establishing predictable patterns across the codebase.