Missing borders on Linux x86

#### Describe the bug

Hello, rendering of a few of the official examples seems broken on Linux x86 (32bit). The `tabs` example:

##### x86

##### x86-64

#### Setup

I can reproduce this on Void (glibc) and Alpine Linux (musl). If you're running on a x86-64 machine, you can reproduce this easily with just a 32bit user space in a container.

##### Containerfile

```
# Alpine 3.24.1-x86 - BUG
FROM docker.io/library/golang@sha256:632e3a67f8e1da34a2e14c805673915a774bebb8322da4ffec804f6e9f10dd86

# Alpine 3.24.1-x86-64 - WORKS
# FROM docker.io/library/golang@sha256:4c9fe60190a2a3350ddc51de80d0224b8a6698d12bdfc999fee45ea9d6c46dbc

RUN apk update && apk upgrade && apk add curl unzip

# v2.0.9
RUN wcurl https://github.com/charmbracelet/bubbletea/archive/73b6d91ac1c3854dd4af046ab5f9e51d3b3b4290.zip \
&& unzip *zip

WORKDIR "/go/bubbletea-73b6d91ac1c3854dd4af046ab5f9e51d3b3b4290/examples/tabs"

CMD ["go", "run", "main.go"]
```

```
podman build . --tag repro
podman run --rm -it repro
```

I'm running Ghostty 1.3.1 and Tmux 3.7b but it's reproducible in other terminals as well without Tmux.

Start with examples/tabs/main.go and reproduce the report using the supplied Containerfile and 32-bit Alpine or Void environment, comparing it with x86-64. The work is done when the tabs example renders its borders on Linux x86 as shown by the working x86-64 output.

Written by the indexing model from the issue text.