Initialize VPNL Discord bot (slash commands + config)

[skylessdev]

Scope

• Node.js project with Discord.js v14 and Ethers.js.
• Env vars: RPC_URL, VPNL_REGISTRY_ADDR, MIN_SCORE=600.
• Register slash commands: /verify, /score, /reverify, /unlink, /status, /gate set-minscore.

Acceptance Criteria

• Bot online and responds to /status.
• Commands visible in #verify.
• Env can be set via Replit Secrets.