Make appliance onboarding and SV2 connection self-explanatory

[keegreil]

Summary

• redirect cached dashboard sessions to /setup when payout configuration is required
• expose explicit, non-secret native SV2 connection metadata in the dashboard projection
• add copyable miner connection guidance to map and detail views
• hide operator controls when the administrative API is disabled
• validate the advertised native SV2 port and tolerate mixed cached API versions

Validation

• npm test -- --run (24 tests)
• npm run build
• dotnet test (234 tests)
• node scripts/security-source-check.mjs
• live Umbrel-dev first-run redirect and health check