Harden restore safety and npm releases

[TheStreamCode]

What changed

• hardens backup validation, restore identity matching, cross-guild permission mapping, and Discord client retry behavior
• adds regression coverage, explicit MCP tool annotations, and current dependencies
• adds repository governance, AGENTS.md, linting, Windows CI, release metadata checks, and npm publishing with provenance
• reduces the npm package to the intended runtime and documentation files

Why

The repository needed production-grade restore safety, reproducible validation, and a complete GitHub/npm release path before its first public package release.

Validation

• npm run preflight
• npm run pack:check
• npm run release:check -- v0.1.0
• git diff --check
• 7 test files / 27 tests passing