`usr/lib/os-release` should not be executable

**Describe the bug**
The file `usr/lib/os-release` is marked as executable. I checked the following image:

```
gcr.io/distroless/static-debian13 latest f39a20497483 56 years ago 3.26 MB
```

**To Reproduce**
Steps to reproduce the behavior:

Run `ls -l usr/lib/os-release` after mounting the image (`podman mount`):

```
# ls -l usr/lib/os-release
-r-xr-xr-x 1 root root 344 1. Jan 1970 usr/lib/os-release
```

**Expected behavior**
The file should not be marked as executable. In Debian proper it is not:

```
$ ls -l /usr/lib/os-release
-rw-r--r-- 1 root root 220 31. Mai 11:20 /usr/lib/os-release
```

**Console Output**
N/A

**Additional context**
N/A

Start by tracing the distroless image build inputs and rules that create or copy usr/lib/os-release. Check how its file mode is set, then rebuild or inspect the image and confirm ls -l usr/lib/os-release reports non-executable permissions matching Debian.

Written by the indexing model from the issue text.