fix(test): clear spy mock calls after beforeEach setup

Added mockClear() calls after creating spies in beforeEach to prevent
setup calls from interfering with test assertions. This fixes test
failures on Windows CI where mock call counts were higher than expected.

Affected tests:
- test/stdio/stderr.test.ts (4 tests)
- test/stdio/stdout.test.ts (preventive fix)

Fixes mock call count assertions to only count calls made during the
actual test, not during beforeEach setup.

Author: jdalton

test/stdio/stderr.test.ts

@@ -47,6 +47,11 @@ describe('stdio/stderr', () => {
     cursorToSpy = vi.spyOn(stderr, 'cursorTo').mockImplementation(() => {})
     // @ts-expect-error - Vitest spy type doesn't match ReturnType<typeof vi.spyOn>
     clearLineSpy = vi.spyOn(stderr, 'clearLine').mockImplementation(() => {})
+
+    // Clear any calls made during setup
+    writeSpy.mockClear()
+    cursorToSpy.mockClear()
+    clearLineSpy.mockClear()
   })
 
   afterEach(() => {

test/stdio/stdout.test.ts

@@ -62,6 +62,12 @@ describe('stdio/stdout', () => {
       .spyOn(stdout, 'clearScreenDown')
       // @ts-expect-error - Vitest mock type doesn't match expected implementation signature
       .mockImplementation(() => {})
+
+    // Clear any calls made during setup
+    writeSpy.mockClear()
+    cursorToSpy.mockClear()
+    clearLineSpy.mockClear()
+    clearScreenDownSpy.mockClear()
   })
 
   afterEach(() => {