refactor(test): reorganize tests into unit and integration directories

Restructure test directory to separate unit tests from integration tests:
- test/unit/ - Fast unit tests (all existing tests)
- test/integration/ - Integration tests requiring TTY/process spawning
  - stdio/mask.test.ts moved here (requires TTY mocking)

Updated vitest config to include both directories.
Fixed relative imports in tests that moved directories.
Fixed esbuild config to use inline envAsBoolean helper.

Test structure now clearly separates concerns and makes it easier
to run fast unit tests vs slower integration tests.

All 5151 tests still pass.

Author: jdalton

.config/esbuild.config.mjs

@@ -7,9 +7,14 @@ import path from 'node:path'
 import { fileURLToPath } from 'node:url'
 import fg from 'fast-glob'
 
-import { envAsBoolean } from '#socketsecurity/lib/env/utils'
 import { getLocalPackageAliases } from '../scripts/utils/get-local-package-aliases.mjs'
 
+// Helper to check boolean env vars
+const envAsBoolean = name => {
+  const value = process.env[name]
+  return value === 'true' || value === '1'
+}
+
 const __dirname = path.dirname(fileURLToPath(import.meta.url))
 const rootPath = path.join(__dirname, '..')
 const srcPath = path.join(rootPath, 'src')

.config/vitest.config.mts

@@ -53,7 +53,16 @@ export default defineConfig({
     environment: 'node',
     include: [
       toGlobPath(
-        path.resolve(projectRoot, 'test/**/*.test.{js,ts,mjs,mts,cjs,cts}'),
+        path.resolve(
+          projectRoot,
+          'test/unit/**/*.test.{js,ts,mjs,mts,cjs,cts}',
+        ),
+      ),
+      toGlobPath(
+        path.resolve(
+          projectRoot,
+          'test/integration/**/*.test.{js,ts,mjs,mts,cjs,cts}',
+        ),
       ),
     ],
     exclude: [