Add master dashboard reporter and settings UI

- New reporter module that pushes firm stats (total accounts, accounts
  traded, in trade) to a configurable master dashboard every 30 seconds
- Add Instance Name and Dashboard URL fields to the settings page
- Register master_dashboard_url and instance_name in settings API
- Seed default (empty) values for new settings in db

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

lib/clients.ts

@@ -1,6 +1,7 @@
 import { TradovateClient } from './tradovate-class';
 import { getFirms, getInstruments } from './db';
 import { resolveContracts } from './contract-resolver';
+import { startReporter } from './reporter';
 
 // Use global to persist the client pool across HMR reloads in dev mode
 const g = global as typeof globalThis & {
@@ -59,6 +60,9 @@ export function getClients(): Map<number, TradovateClient> {
 
             // Schedule daily resolve at midnight
             scheduleDailyResolve();
+
+            // Start master dashboard reporter
+            startReporter();
         } catch (err) {
             console.error('[clients] Failed to initialize clients', err);
         }