## Description

Pairing a Logitech MX Anywhere 3 from the stock Bluetooth panel enters an automatic loop: the row alternates between pairing/connecting states roughly once per second without further user input. The device may connect transiently, but it is not bonded and will not reconnect.

The USB adapter, kernel driver, firmware, BlueZ service, discovery, and direct `bluetoothctl` pairing all work. The failure is in the stock `bt-agent.service` integration.

## Steps to reproduce

1. Start an Omarchy session with `bt-agent.service` enabled and active.
2. Open the Bluetooth panel with `Super + Ctrl + B`.
3. Put a Logitech MX Anywhere 3 into pairing mode.
4. Click **Pair** once.
5. Observe the row repeatedly alternate between pairing and connecting without any additional input.

## Actual behavior

`bluetoothd` repeatedly rejects the authorization request, while the user service logs an interactive prompt despite having no terminal:

```text
bluetoothd: src/device.c:new_auth() No agent available for request type 2
bluetoothd: device_confirm_passkey: Operation not permitted
bt-agent: Authorize this device pairing (yes/no)? Device: MX Anywhere 3 (...)
```

The prompt and pairing attempt repeat about once per second. `systemctl --user stop bt-agent.service` can also remain stuck in `deactivating (stop-sigterm)` until the `bt-agent` process is killed.

## Expected behavior

One click should authorize a Just Works pairing, create a persistent bond, trust the device, and connect it. The panel should terminate a failed attempt instead of continually retrying.

## Root cause evidence

The packaged unit says that `NoInputNoOutput` auto-accepts pairing:

```ini
ExecStart=/usr/bin/bt-agent -c NoInputNoOutput
```

However, `-c NoInputNoOutput` in `bluez-tools` selects the advertised I/O capability; it does not make every authorization callback non-interactive. On this system, `bt-agent` still reads an `Authorize this device pairing (yes/no)?` prompt from stdin. Because the systemd user service has no interactive stdin, authorization never completes while the panel continues launching pairing attempts.

After runtime-masking and killing `bt-agent.service`, the same mouse paired immediately through an interactive `bluetoothctl` agent. BlueZ then reported:

```text
Paired: yes
Bonded: yes
Trusted: yes
Connected: yes
```

This differs from #6992 (missing `bluez-tools`) and #8614 (continuous inquiry/page timeout): `/usr/bin/bt-agent` is installed and active here, and the decisive failure is its unattended authorization prompt.

## System details

- Omarchy: 4.0.2-1
- Kernel: 7.1.9.arch1-2
- BlueZ / bluez-utils: 5.87-2
- bluez-tools: 0.2.0-6
- Adapter: TP-Link UB500 (`2357:0604`), Realtek RTL8761BU firmware loaded successfully
- Device: Logitech MX Anywhere 3 (Bluetooth LE HID)
- CPU: AMD Ryzen 9 9950X3D
- GPU: AMD Radeon RX 9070 XT

## Suggested direction

Use a pairing agent whose unattended Just Works behavior is explicit and testable (potentially BlueZ's maintained `bluetoothctl --agent NoInputNoOutput`) rather than the old `bluez-tools` agent, and ensure the panel treats a failed pairing attempt as terminal instead of automatically re-entering the pair/connect cycle.