subpath imports should play well with project references

@andrewbranch y travaille déjà.

Depuis le 12/12/2025.

### 🔎 Search Terms

tsconfig, resolve, package, imports, module, references

### 🕗 Version & Regression Information

5.9.3

TS project refererences in combination with subpath imports mapping to installed packages break Node.js projects.

### ⏯ Playground Link

_No response_

### 💻 Code

```ts
// @scope/alice/src/index.ts
import "@scope/bob/module"; // ok
import "#bob/module"; // breaks
```

```jsonc
// @scope/alice/tsconfig.json
{
"files": [],
"include": [],
"references": { "path": "./tsconfig.other.json" }
}
```

```jsonc
// @scope/alice/tsconfig.other.json
// appears in the error message, but its content should be irrelevant, given
// that @scope/bob/module imports work.
{
"compilerOptions":
{
"composite": true,
// ...
},
"files": [
// whatever, except for files from node_modules, therefore excluding @scope/bob
],
}
```

```json
{
"// package.json": "",
"name": "@scope/alice",
"type": "module",
"imports": {
"#bob/*": "@scope/bob/*"
},
"dependencies": {
"@scope/bob": "*"
},
"// ...": ""
}
```

```sh
tsc --build --noEmit
```

### 🙁 Actual behavior

An error of this kind:

```txt
src/index.ts:3:8 - error TS6307: File '/absolute/path/to/mono-repo/packages/bob/src/module/index.ts' is not listed within the file list of project '/absolute/path/to/mono-repo/packages/alice/tsconfig.other.json'. Projects must list all files or use an 'include' pattern.
File is ECMAScript module because '/absolute/path/to/mono-repo/packages/bob/package.json' has field "type" with value "module"

import "#bob/module"; // breaks
~~~~~~~~~~~~~
```

### 🙂 Expected behavior

Should build just fine, since subpath imports are nothing but a string rewriting mechanism (think: URL shortener). TSC should recognize that `#bob/*` refers to the modules in the external package `@scope/bob/*` from within `node_modules`, rather than treating it as project internal.

### Additional information about the issue

This can't be reproduced on the playground. I am willing to setup a repro repo, if the code in this issue is not sufficient to figure out what's going on.