feat(new): track provider health state

AgentCompany-New/src/main/database/migrations/008-provider-health.ts

@@ -0,0 +1,6 @@
+export const providerHealthSchema = `
+  alter table providers add column auth_state text not null default 'unconfigured';
+  alter table providers add column health_state text not null default 'unchecked';
+  alter table providers add column last_checked_at text;
+  alter table providers add column last_error text;
+`;