Add manual IP fallback during pairing

[jelledelaender]

Goal

Add a fallback path for users whose Homey cannot discover SoundTouch speakers via mDNS.

Context

Discovery works on normal LANs, but office networks, VLANs, guest Wi-Fi, or blocked multicast can prevent speakers from appearing. Users should still be able to add a speaker if they know its IP address.

Scope

• Add a manual IP entry path in pairing.
• Validate the entered IP by calling the Bose /info endpoint.
• Use the Bose device ID from /info as data.id when available.
• Store the IP in store.address and settings.ip_address.
• Keep the automatic discovery path as the default.

Acceptance Criteria

• A user can pair a speaker by IP when mDNS returns no devices.
• Invalid/unreachable IPs show a clear error.
• Existing preset settings behavior is unchanged.
• npx homey app validate passes.