feat: cross-platform build system migration (Node.js)

[edithatogo]

Description

The current PowerShell-based sync and validation scripts are not cross-platform, which limits contributions from macOS and Linux users.

Proposed Solution

• Migrate sync-adapters.ps1 to scripts/sync-adapters.js.
• Migrate �alidate-adapters.ps1 to scripts/validate-adapters.js.
• Add package.json for standardized npm scripts (
  pm run sync,
  pm run validate).
• Update documentation and remove legacy PS1 scripts.