SAM Build Not Mounting Lambda Code in `/var/task` During `sam local start api` on Windows

### Description:
When using `npm run build` and running `sam local start api` or `sam local invoke`, SAM builds the Lambda image on the fly. However, it seems that the Lambda code is not being mounted correctly in `/var/task`, which results in an empty directory. This prevents the Lambda from executing properly.

### Context:
I expect SAM to mount the built Lambda sources from `dist/` into `/var/task` inside the container. However, the `/var/task` directory is empty, making it impossible to execute the Lambda function via `sam local start api`.

I've tried multiple solutions but couldn't resolve this issue. It might be related to switching from a Linux development environment to a Windows environment.

In my `template.yml`, I point the `CodeUri` to the compiled code in the `dist/` directory, like this:

```yaml
CodeUri: dist/lambdas/myFunction/
```

### Expected behavior:
The compiled Lambda code should be mounted into `/var/task` inside the container to allow the Lambda function to execute properly.

### Environment:
- **Operating System**: Windows
- **SAM CLI Version**: Tested with version 1.120
- **Docker Version**: 26.1.0-rd
- **Docker setup**: Running on WSL2
- **Custom Lambda Image**: Defined in `template.yml`

### Steps to reproduce:
1. Run `npm run build`. [npx tsc --project tsconfig.build.json]
2. Start the Lambda function using either `sam local start api` or `sam local invoke`.
3. Inspect the container, and observe that `/var/task` is empty.

### Possible suggestions or fixes:
- Ensure that SAM properly mounts the Lambda code into the `/var/task` directory during execution on Windows.
- Investigate if the issue is related to file mounting differences between Linux and Windows.

Thank you for your help!