Add Settings -> Database viewer (Adminer) for local devs and any admin

Local dev gets an unauthenticated Adminer instance bound to loopback
only. In production, any account with is_admin=true can open it -
the app mints a short-lived token from a live admin session, which
Nginx's new db.ciagent.org block exchanges for a session cookie that
re-checks admin status on every request, instead of a shared static
password that wouldn't scale to multiple admins or revoke live.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

apps/web/lib/api-client.ts

@@ -11,6 +11,7 @@ import type {
   CompanyUpdatePayload,
   ConfirmPasswordResetPayload,
   DashboardAnalytics,
+  DbViewerSessionResponse,
   DiscoverCompanyRequest,
   DiscoveredCompanyProfile,
   IpBan,
@@ -166,6 +167,9 @@ export const api = {
 
   listSystemSecrets: () => request<SystemSecretStatus[]>("/api/v1/system/secrets"),
 
+  createDbViewerSession: () =>
+    request<DbViewerSessionResponse>("/api/v1/db-viewer/session", { method: "POST" }),
+
   setSystemSecret: (key: string, payload: SetSystemSecretPayload) =>
     request<SystemSecretStatus>(`/api/v1/system/secrets/${key}`, {
       method: "PUT",