perf: streamline provider and agent startup loading #185

Avoids loading the full provider catalog on startup
Prewarms project config in the background
Prevents duplicate worktree-scoped config requests

packages/ui/src/components/sections/providers/ProvidersPage.test.ts

@@ -0,0 +1,9 @@
+import { describe, expect, test } from 'bun:test';
+import { shouldLoadAvailableProviders } from './providerAvailability';
+
+describe('ProvidersPage available provider loading', () => {
+  test('loads available providers only in add-provider mode', () => {
+    expect(shouldLoadAvailableProviders(false)).toBe(false);
+    expect(shouldLoadAvailableProviders(true)).toBe(true);
+  });
+});