fix(frontend): remove test types from base tsconfig for CI build

The base tsconfig.json had types: ["vitest/globals", "@testing-library/jest-dom/vitest"]
which are devDependencies only installed during development. CI production
builds with npm ci --production don't include these, causing TS2688 errors.

Solution:

Remove types array from tsconfig.json (let TS auto-discover available types)
Simplify tsconfig.build.json to only exclude test files
Add triple-slash type references to test setup file
Add typecheck config to vitest.config.ts
This ensures:

Production builds work without devDependencies
Test files still have proper type definitions
No JSX.IntrinsicElements errors from missing React types

frontend/src/components/__tests__/DNSProviderSelector.test.tsx

@@ -137,7 +137,7 @@ describe('DNSProviderSelector', () => {
       isLoading: false,
       isError: false,
       error: null,
-    } as any)
+    } as unknown as ReturnType<typeof useDNSProviders>)
   })
 
   describe('Rendering', () => {
@@ -232,7 +232,7 @@ describe('DNSProviderSelector', () => {
         isLoading: false,
         isError: false,
         error: null,
-      } as any)
+      } as unknown as ReturnType<typeof useDNSProviders>)
 
       renderWithClient(<DNSProviderSelector value={undefined} onChange={mockOnChange} />)
 
@@ -254,7 +254,7 @@ describe('DNSProviderSelector', () => {
         isLoading: false,
         isError: false,
         error: null,
-      } as any)
+      } as unknown as ReturnType<typeof useDNSProviders>)
 
       renderWithClient(<DNSProviderSelector value={undefined} onChange={mockOnChange} />)
 
@@ -272,7 +272,7 @@ describe('DNSProviderSelector', () => {
         isLoading: true,
         isError: false,
         error: null,
-      } as any)
+      } as unknown as ReturnType<typeof useDNSProviders>)
 
       renderWithClient(<DNSProviderSelector value={undefined} onChange={mockOnChange} />)
 
@@ -286,7 +286,7 @@ describe('DNSProviderSelector', () => {
         isLoading: true,
         isError: false,
         error: null,
-      } as any)
+      } as unknown as ReturnType<typeof useDNSProviders>)
 
       renderWithClient(<DNSProviderSelector value={undefined} onChange={mockOnChange} />)
 
@@ -301,7 +301,7 @@ describe('DNSProviderSelector', () => {
         isLoading: false,
         isError: false,
         error: null,
-      } as any)
+      } as unknown as ReturnType<typeof useDNSProviders>)
 
       renderWithClient(<DNSProviderSelector value={undefined} onChange={mockOnChange} />)
 
@@ -316,7 +316,7 @@ describe('DNSProviderSelector', () => {
         isLoading: false,
         isError: false,
         error: null,
-      } as any)
+      } as unknown as ReturnType<typeof useDNSProviders>)
 
       renderWithClient(<DNSProviderSelector value={undefined} onChange={mockOnChange} />)
 
@@ -421,7 +421,7 @@ describe('DNSProviderSelector', () => {
         isLoading: true,
         isError: false,
         error: null,
-      } as any)
+      } as unknown as ReturnType<typeof useDNSProviders>)
 
       renderWithClient(<DNSProviderSelector value={undefined} onChange={mockOnChange} />)