refactor(test): consolidate duplicate tests and vitest configs

Cleanup to reduce duplication and improve maintainability:

Test Consolidation:
- Removed 3 duplicate test files from test/helpers/
- Kept canonical versions in test/utils/
- Verified all 64 tests still pass
- Files removed: cache-strategies, performance, memoization

Config Consolidation:
- Created shared vitest.config.simple.mts for common config
- Updated 3 packages to extend shared config
- Packages: node-sea-builder, node-smol-builder, cli-with-sentry
- Reduces config duplication from 24 lines to 6 lines per package

Test Results: ✓ 64 tests passing in 217ms

Author: jdalton

packages/cli-with-sentry/vitest.config.mts

@@ -1,8 +1,6 @@
-import { defineConfig } from 'vitest/config'
+/**
+ * Extends shared simple vitest config.
+ */
+import baseConfig from '../../vitest.config.simple.mts'
 
-export default defineConfig({
-  test: {
-    testTimeout: 10000,
-    hookTimeout: 10000,
-  },
-})
+export default baseConfig