perf(build,test): apply socket-sdk-js optimizations

Apply build and test optimizations from socket-sdk-js for improved
performance and consistency across Socket projects.

Build System Enhancements:
- Enable minification in esbuild for production builds
- Enable tree-shaking optimization
- Add NODE_ENV constant definition for optimization
- Integrate local package aliases for monorepo development

Test Configuration Optimizations:
- Add Vitest cache directory configuration
- Maximize thread pool (16 threads) for parallel execution
- Add concurrent test execution within suites
- Enable bail-on-first-failure in CI for faster feedback
- Add comprehensive documentation for isolate: false tradeoffs

These optimizations align socket-lib with socket-sdk-js patterns:
- Faster builds with minification and tree-shaking
- Faster test execution with optimized thread pool
- Better monorepo development with local package aliases
- Consistent configuration across Socket projects

Author: jdalton

.config/esbuild.config.mjs

@@ -7,6 +7,8 @@ import path from 'node:path'
 import { fileURLToPath } from 'node:url'
 import fg from 'fast-glob'
 
+import { getLocalPackageAliases } from '../scripts/utils/get-local-package-aliases.mjs'
+
 const __dirname = path.dirname(fileURLToPath(import.meta.url))
 const rootPath = path.join(__dirname, '..')
 const srcPath = path.join(rootPath, 'src')
@@ -31,16 +33,26 @@ export const buildConfig = {
   platform: 'node',
   target: 'node18',
   sourcemap: true,
-  // Library code should be readable.
-  minify: false,
-  // Can't tree-shake without bundling.
-  treeShaking: false,
+  // Minify for production builds (can be overridden in watch mode)
+  minify: true,
+  // Tree-shaking optimization
+  treeShaking: true,
   metafile: true,
   logLevel: 'info',
 
+  // Alias local packages when available (dev mode).
+  alias: getLocalPackageAliases(rootPath),
+
   // Note: Cannot use "external" with bundle: false
   // esbuild automatically treats all imports as external when not bundling
 
+  // Define constants for optimization
+  define: {
+    'process.env.NODE_ENV': JSON.stringify(
+      process.env.NODE_ENV || 'production',
+    ),
+  },
+
   // Banner for generated code
   banner: {
     js: '/* Socket Lib - Built with esbuild */',

.config/vitest.config.mts

@@ -16,6 +16,7 @@ const isCoverageEnabled =
   process.argv.some(arg => arg.includes('coverage'))
 
 export default defineConfig({
+  cacheDir: path.resolve(projectRoot, '.cache/vitest'),
   resolve: {
     preserveSymlinks: false,
     extensions: isCoverageEnabled
@@ -55,19 +56,42 @@ export default defineConfig({
         : [path.resolve(projectRoot, 'test/npm/**')]),
     ],
     reporters: ['default'],
+    // Optimize test execution for speed
+    // Threads are faster than forks
     pool: 'threads',
     poolOptions: {
       threads: {
+        // Maximize parallelism for speed
+        // During coverage, use single thread for deterministic execution
         singleThread: isCoverageEnabled,
         maxThreads: isCoverageEnabled ? 1 : 16,
         minThreads: isCoverageEnabled ? 1 : 4,
-        // Use isolate: false for performance and test compatibility
+        // IMPORTANT: isolate: false for performance and test compatibility
+        //
+        // Tradeoff Analysis:
+        // - isolate: true  = Full isolation, slower, breaks nock/module mocking
+        // - isolate: false = Shared worker context, faster, mocking works
+        //
+        // We choose isolate: false because:
+        // 1. Significant performance improvement (faster test runs)
+        // 2. HTTP mocking works correctly across all test files
+        // 3. Vi.mock() module mocking functions properly
+        // 4. Test state pollution is prevented through proper beforeEach/afterEach
+        // 5. Our tests are designed to clean up after themselves
         isolate: false,
         useAtomics: true,
       },
     },
+    // Reduce timeouts for faster failures
     testTimeout: 10_000,
     hookTimeout: 10_000,
+    // Speed optimizations
+    sequence: {
+      // Run tests concurrently within suites
+      concurrent: true,
+    },
+    // Bail early on first failure in CI
+    bail: process.env.CI ? 1 : 0,
     server: {
       deps: {
         inline: isCoverageEnabled ? [/@socketsecurity\/lib/, 'zod'] : ['zod'],