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/merge-stream/index.js

@@ -0,0 +1,41 @@
+'use strict';
+
+const { PassThrough } = require('stream');
+
+module.exports = function (/*streams...*/) {
+  var sources = []
+  var output  = new PassThrough({objectMode: true})
+
+  output.setMaxListeners(0)
+
+  output.add = add
+  output.isEmpty = isEmpty
+
+  output.on('unpipe', remove)
+
+  Array.prototype.slice.call(arguments).forEach(add)
+
+  return output
+
+  function add (source) {
+    if (Array.isArray(source)) {
+      source.forEach(add)
+      return this
+    }
+
+    sources.push(source);
+    source.once('end', remove.bind(null, source))
+    source.once('error', output.emit.bind(output, 'error'))
+    source.pipe(output, {end: false})
+    return this
+  }
+
+  function isEmpty () {
+    return sources.length == 0;
+  }
+
+  function remove (source) {
+    sources = sources.filter(function (it) { return it !== source })
+    if (!sources.length && output.readable) { output.end() }
+  }
+}