Error pairing with Hue Bridge

Here's a fun one.

With a fresh setup:
- Freshly-installed official Hue app (iOS 26)
- Fresh install of Bifrost on its own VM from source (to avoid weird Home Assistant port collisions with `:80/:443`)
- New certificate generated, etc

I'm getting pairing errors:

```
Nov 04 23:19:18 bifrost bifrost[548]: bifrost::server: Config changed, saving..
Nov 04 23:22:13 bifrost bifrost[548]: bifrost::routes::api: post: b"{\"devicetype\":\"Hue#iPhone\",\"generateclientkey\":true}"
Nov 04 23:22:13 bifrost bifrost[548]: bifrost::routes: V1 request failed: No such file or directory (os error 2)
Nov 04 23:22:14 bifrost bifrost[548]: bifrost::routes: V1 request failed: No such file or directory (os error 2)
Nov 04 23:22:15 bifrost bifrost[548]: bifrost::routes: V1 request failed: No such file or directory (os error 2)
Nov 04 23:22:16 bifrost bifrost[548]: bifrost::routes: V1 request failed: No such file or directory (os error 2)
Nov 04 23:22:17 bifrost bifrost[548]: bifrost::routes: V1 request failed: No such file or directory (os error 2)
Nov 04 23:22:18 bifrost bifrost[548]: bifrost::routes: V1 request failed: No such file or directory (os error 2)
Nov 04 23:22:20 bifrost bifrost[548]: bifrost::routes: V1 request failed: No such file or directory (os error 2)
Nov 04 23:22:21 bifrost bifrost[548]: bifrost::routes: V1 request failed: No such file or directory (os error 2)
Nov 04 23:22:21 bifrost bifrost[548]: bifrost::routes: V1 request failed: No such file or directory (os error 2)
Nov 04 23:22:22 bifrost bifrost[548]: bifrost::routes: V1 request failed: No such file or directory (os error 2)
Nov 04 23:22:23 bifrost bifrost[548]: bifrost::routes: V1 request failed: No such file or directory (os error 2)
... etc
```

I'm running Bifrost under `systemd`:

```
root@bifrost:~# systemctl cat bifrost
# /etc/systemd/system/bifrost.service
[Unit]
Description=Bifrost Hue Emulator
After=network.target

[Service]
ExecStart=/usr/local/bin/bifrost
Restart=on-failure
WorkingDirectory=/etc/bifrost

[Install]
WantedBy=multi-user.target
```

Here's the *extra* weird thing: when I copy `config.yml` to `~/` and run `bifrost` in the shell, it came up fine, paired, and even showed the Z2M groups I'd created.

Then I `cp *.yml /etc/bifrost/ && cp cert.pem /etc/bifrost/` and started Bifrost again. It worked!

Fun fun fun! I couldn't track down where `V1 request failed...` was coming from in the code, but then I'm not familiar with Rust so 🤷🏻
Any ideas?