bug: broke AL2 terminal

### Checks

- [x] I have searched [github.com/aws/amazon-q-developer-cli/issues](https://github.com/aws/amazon-q-developer-cli/issues?q=) and there are no duplicates of my issue
- [x] I have run `q doctor` in the affected terminal session
- [x] I have run `q restart` and replicated the issue again

### Operating system

AL2

### Expected behaviour

### Actual behaviour

### Steps to reproduce

After installing Q CLI, my terminal becomes unusable, showing gibberish.
Removing the following line from my zshrc fixes it:

```
# Amazon Q post block. Keep at the bottom of this file.
[[ -f "${HOME}/.local/share/amazon-q/shell/zshrc.post.zsh" ]] && builtin source "${HOME}/.local/share/amazon-q/shell/zshrc.post.zsh"
```

### Environment

```yaml
(25-07-21 19:00:22) <0> [~]
dev-dsk-hazout-1a-953df417 % q diagnostic

[q-details]
version = "1.12.6"
hash = "9c083cf7e8f7de077eb116c3993823b82f71ca12"
date = "2025-07-18T21:39:05.889985Z (3d ago)"
variant = "minimal"

[system-info]
chip = "AMD EPYC 7R13 Processor"
total-cores = 16
memory = "123.22 GB"

[system-info.os.linux]
kernel_version = "5.10.238-215.956.amzn2int.x86_64"
id = "amzn"
name = "Amazon Linux"
pretty_name = "Amazon Linux 2"
version_id = "2"
version = "2"
variant = "internal"

[environment]
cwd = "/local/home/USER"
cli-path = "/local/home/USER"
os = "Linux"
shell-path = "/local/home/USER/.toolbox/tools/toolbox/1.1.1986.0/toolbox-exec"
shell-version = "5.8"
install-method = "toolbox"

[env-vars]
DISPLAY = ":0"
PATH = "/home/USER/.local/share/mise/installs/node/18.20.2/bin:/home/USER/.local/share/mise/installs/python/3.12.3/bin:/home/USER/.toolbox/bin:/home/USER/.toolbox/bin:/usr/local/bin:/usr/bin:/home/USER/.local/bin:/home/USER/.local/share/JetBrains/Toolbox/scripts:/home/USER/bin:/usr/local/sbin:/usr/sbin:/apollo/env/OdinTools/bin:/apollo/env/envImprovement/bin:/apollo/env/AAAWorkspaceSupport/bin:/apollo/env/ApolloCommandLine/bin:/apollo/env/BarkCLI/bin:/apollo/env/RemoteOverrideSupport/bin:/apollo/env/ScalingPlannerCLI/bin:/apollo/env/TardigradeServiceCoral2Json/bin:/apollo/env/VMAProxyCLI/bin:/apollo/env/WHOFleetTemplates/bin"
Q_SET_PARENT_CHECK = "1"
SHELL = "/bin/zsh"
TERM = "xterm-256color"
XDG_CURRENT_DESKTOP = "MATE"
XDG_SESSION_TYPE = "x11"

(25-07-21 19:07:25) <0> [~]
dev-dsk-hazout-1a-953df417 %
```