fix: resolve unit test failures in theme mocking

- Replace file-based mocks with inline Jest mocks to avoid module name conflicts
- Update themes.test.js and monitor.test.jsx to use proper inline mock definitions
- Remove physical __mocks__ directories that were causing Jest duplication warnings
- Ensure tests use expected mock values instead of actual theme values

Fixes unit tests that were failing due to mock configuration issues after
upstream merge integration.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

Author: takaokouji

test/unit/components/monitor.test.jsx

@@ -4,8 +4,23 @@ import DefaultMonitor from '../../../src/components/monitor/default-monitor';
 import Monitor from '../../../src/components/monitor/monitor';
 import {DARK_THEME, DEFAULT_THEME} from '../../../src/lib/themes';
 
-jest.mock('../../../src/lib/themes/default');
-jest.mock('../../../src/lib/themes/dark');
+jest.mock('../../../src/lib/themes/default', () => ({
+    blockColors: {
+        motion: {
+            primary: '#111111'
+        },
+        text: '#444444'
+    }
+}));
+
+jest.mock('../../../src/lib/themes/dark', () => ({
+    blockColors: {
+        motion: {
+            primary: '#AAAAAA'
+        },
+        text: '#BBBBBB'
+    }
+}));
 
 describe('Monitor Component', () => {
     test('it selects the correct colors based on default theme', () => {

test/unit/util/themes.test.js

@@ -8,8 +8,41 @@ import {
 import {injectExtensionBlockTheme, injectExtensionCategoryTheme} from '../../../src/lib/themes/blockHelpers';
 import {detectTheme, persistTheme} from '../../../src/lib/themes/themePersistance';
 
-jest.mock('../../../src/lib/themes/default');
-jest.mock('../../../src/lib/themes/dark');
+jest.mock('../../../src/lib/themes/default', () => ({
+    blockColors: {
+        motion: {
+            primary: '#111111',
+            secondary: '#222222',
+            tertiary: '#333333'
+        },
+        pen: {
+            primary: '#121212',
+            secondary: '#232323',
+            tertiary: '#343434'
+        },
+        text: '#444444',
+        workspace: '#555555'
+    }
+}));
+
+jest.mock('../../../src/lib/themes/dark', () => ({
+    blockColors: {
+        motion: {
+            primary: '#AAAAAA'
+        },
+        pen: {
+            primary: '#FFFFFF',
+            secondary: '#EEEEEE',
+            tertiary: '#DDDDDD'
+        },
+        text: '#BBBBBB'
+    },
+    extensions: {
+        pen: {
+            blockIconURI: 'darkPenIcon'
+        }
+    }
+}));
 
 describe('themes', () => {
     let serializeToString;