bundler: give import * of a lifted CommonJS module its own namespace object

docs/bundler/index.mdx

@@ -1415,11 +1415,22 @@ In each case the member access compiles to a direct reference to `object`, the `
 
 Assignments (`z.x = 1`), optional chains, and non-literal computed keys (`z[key]`) are left as property accesses; `z["object"]` is treated like `z.object`. `export default someImport` is followed only when it ends at a namespace; a default that snapshots a `let` export keeps snapshot semantics.
 
-The same applies to the default import of a CommonJS module whose `exports.x = ...` assignments the bundler lifted to ES module exports, such as `react` and `scheduler`. The default import of a CommonJS module is its `module.exports`, which is that module's namespace, so `import React from "react"; React.useState()` compiles to a direct call of the lifted `useState` binding. The namespace object is created only when `React` itself is used as a value, and it lists the exports in assignment order, like `module.exports` does. A write through it, `React.useLayoutEffect = React.useEffect`, assigns the lifted binding, so every importer sees the new value, the same as a write to `module.exports`. `React.default`, and `ns.default` on `import * as ns`, is the lifted `default` export when the module has one, and otherwise the namespace itself, as `module.exports` is in Node. A module that sets both `exports.__esModule` and `exports.default` keeps its CommonJS wrapper when the importer is not an ES module by type (`.mjs`, `.mts`, or `"type": "module"`), because the default import then depends on that flag at run time. An `import()` of a module that does not set both resolves to that same namespace object as `default`, with or without code splitting.
+The same applies to the default import of a CommonJS module whose `exports.x = ...` assignments the bundler lifted to ES module exports, such as `react` and `scheduler`. The default import of a CommonJS module is its `module.exports` object, so `import React from "react"; React.useState()` compiles to a direct call of the lifted `useState` binding. The `module.exports` object is created only when `React` itself is used as a value, and it lists the exports in assignment order. A write through it, `React.useLayoutEffect = React.useEffect`, assigns the lifted binding, so every importer sees the new value, the same as a write to `module.exports`. `React.default` is the lifted `default` export when the module has one, and otherwise `undefined`. `import * as ns` gives a separate namespace object, as in Node: `ns.default` is that `module.exports` object (the value a default import binds), followed by the named exports, and `ns.useState` still compiles to the lifted binding. A module that sets both `exports.__esModule` and `exports.default` keeps its CommonJS wrapper when the importer is not an ES module by type (that is, not a `.mjs` or `.mts` file and not in a `"type": "module"` package), because the default import and `ns.default` then depend on that flag at run time. An `import()` resolves to that same `module.exports` object as `default`, with or without code splitting, except that an importer that is not an ES module by type gets `exports.default` from a module that sets both. A lifted CommonJS file that is itself an entry point of the build is the other exception: its output file exports its own `exports.default` as `default`, and so does an `import()` of it.
+
+In short, for a lifted CommonJS module `dep`:
+
+| How `dep` is reached                                                                                                                                                               | What you get                                                                                                                   |
+| ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------ |
+| `import d from "./dep"`, `import { default as d }`, `export { default } from`                                                                                                      | `module.exports`                                                                                                               |
+| `import * as ns` / `export * as ns from`                                                                                                                                           | a namespace object: `ns.default` is `module.exports`, then the named exports; `ns.x` binds the lifted `x`                      |
+| `import("./dep")`, same chunk or split chunk                                                                                                                                       | that namespace shape: `.default` is `module.exports`                                                                           |
+| `require("./dep")`                                                                                                                                                                 | `module.exports`                                                                                                               |
+| any of the above from an importer that is not an ES module by type (not `.mjs`, `.mts`, or `"type": "module"`), when `dep` assigns both `exports.__esModule` and `exports.default` | `default` is `exports.default`, as `bun run` gives it: static imports keep the CommonJS wrapper, a split `import()` unwraps it |
+| `dep` is itself an entry point of the build                                                                                                                                        | its output file, and an `import()` of it, export `exports.default` as `default` (#12463)                                       |
 
 ### deprecatedNamespaceObjectSetters
 
-Default `true`. When a namespace object does have to be created, each property currently gets a getter and a setter; the setter accepts `ns.foo = value` without throwing (reads still return the module's binding). Set this to `false` to emit getter-only namespace objects, which is what a future Bun release will do unconditionally. The namespace of a lifted CommonJS module is not affected: it stands in for `module.exports`, so its setters assign the lifted bindings either way.
+Default `true`. When a namespace object does have to be created, each property currently gets a getter and a setter; the setter accepts `ns.foo = value` without throwing (reads still return the module's binding). Set this to `false` to emit getter-only namespace objects, which is what a future Bun release will do unconditionally. The `module.exports` object of a lifted CommonJS module is not affected: its setters assign the lifted bindings either way.
 
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