refactor(core): centralize path validation and allow temp dir access for tools (#17185)

Co-authored-by: Your Name <joshualitt@google.com>

packages/cli/src/ui/hooks/useGeminiStream.test.tsx

@@ -56,6 +56,7 @@ const MockedGeminiClientClass = vi.hoisted(() =>
     this.startChat = mockStartChat;
     this.sendMessageStream = mockSendMessageStream;
     this.addHistory = vi.fn();
+    this.getCurrentSequenceModel = vi.fn();
     this.getChat = vi.fn().mockReturnValue({
       recordCompletedToolCalls: vi.fn(),
     });
@@ -75,6 +76,13 @@ const MockedUserPromptEvent = vi.hoisted(() =>
 );
 const mockParseAndFormatApiError = vi.hoisted(() => vi.fn());
 
+const MockValidationRequiredError = vi.hoisted(
+  () =>
+    class extends Error {
+      userHandled = false;
+    },
+);
+
 vi.mock('@google/gemini-cli-core', async (importOriginal) => {
   const actualCoreModule = (await importOriginal()) as any;
   return {
@@ -82,6 +90,7 @@ vi.mock('@google/gemini-cli-core', async (importOriginal) => {
     GitService: vi.fn(),
     GeminiClient: MockedGeminiClientClass,
     UserPromptEvent: MockedUserPromptEvent,
+    ValidationRequiredError: MockValidationRequiredError,
     parseAndFormatApiError: mockParseAndFormatApiError,
     tokenLimit: vi.fn().mockReturnValue(100), // Mock tokenLimit
   };
@@ -221,6 +230,7 @@ describe('useGeminiStream', () => {
       getApprovalMode: () => ApprovalMode.DEFAULT,
       getUsageStatisticsEnabled: () => true,
       getDebugMode: () => false,
+      getWorkingDir: () => '/working/dir',
       addHistory: vi.fn(),
       getSessionId() {
         return 'test-session-id';
@@ -228,6 +238,7 @@ describe('useGeminiStream', () => {
       setQuotaErrorOccurred: vi.fn(),
       getQuotaErrorOccurred: vi.fn(() => false),
       getModel: vi.fn(() => 'gemini-2.5-pro'),
+      getContentGenerator: vi.fn(),
       getContentGeneratorConfig: vi
         .fn()
         .mockReturnValue(contentGeneratorConfig),
@@ -1671,6 +1682,7 @@ describe('useGeminiStream', () => {
 
       const testConfig = {
         ...mockConfig,
+        getContentGenerator: vi.fn(),
         getContentGeneratorConfig: vi.fn(() => ({
           authType: mockAuthType,
         })),