reconstruct and build @anthropic-ai/claude-code source from source map

- Extract 4756 source files from cli.js.map (57MB)
- Set up Bun build system with bun:bundle feature flag shim
- Configure 90+ compile-time feature flags matching production defaults
- Inject MACRO constants (VERSION, BUILD_TIME, etc.)
- Create stubs for private packages (color-diff-napi, modifiers-napi, etc.)
- Install all public dependencies via pnpm
- Patch commander v14 to allow multi-char short flags (-d2e)
- Build output: dist/cli.js (22MB), verified working

claude-code-source/node_modules/asynckit/lib/async.js

@@ -0,0 +1,34 @@
+var defer = require('./defer.js');
+
+// API
+module.exports = async;
+
+/**
+ * Runs provided callback asynchronously
+ * even if callback itself is not
+ *
+ * @param   {function} callback - callback to invoke
+ * @returns {function} - augmented callback
+ */
+function async(callback)
+{
+  var isAsync = false;
+
+  // check if async happened
+  defer(function() { isAsync = true; });
+
+  return function async_callback(err, result)
+  {
+    if (isAsync)
+    {
+      callback(err, result);
+    }
+    else
+    {
+      defer(function nextTick_callback()
+      {
+        callback(err, result);
+      });
+    }
+  };
+}