Add a customizable Remote device name

[enaboapps]

Summary

Replace the hard-coded Remote identity sent during pairing with a privacy-safe, editable name. Default to the device model, keep the preference local, and synchronize it to authenticated paired computers.

Acceptance criteria

• Add a nullable Remote-name preference without changing the storage key.
• Use expo-device model name as the default and Switchify Remote as the fallback; never use the user-editable system device name.
• Add an accessible Settings editor with validation, Save, and Use device model actions.
• Send the resolved name in pairing requests and as optional authenticated connection.ping metadata.
• Save offline changes and retry synchronization on reconnect without blocking connection or pointer-profile negotiation.
• Keep protocol v1, BLE identifiers, pairing identity, and persisted pairing data compatible.
• Add unit, integration, accessibility, compatibility, and physical-smoke documentation coverage.
• Run npm run validate and open a draft PR with evidence.

PC counterpart

The linked Switchify PC issue will accept and persist authenticated name updates.
PC counterpart: switchifyapp/switchify-pc#639