App: Add FOTA to connectors to update devices from code

[DennisMoschina]

Summary

Add Firmware Over-The-Air (FOTA) support to the OpenEarable connector so that firmware updates can be triggered programmatically — without requiring the OpenEarable app.

Motivation

Currently, updating device firmware over the air requires using the OpenWearable app. There is no way for developers or automated pipelines to initiate a FOTA update from code. The firmware already supports FOTA via MCUmgr (mcumgr_upload.sh + signed .bin artifacts), and GitHub releases/PR builds are published automatically — the missing piece is a connector-level API to drive the update.

Requirements

The connector should provide a FOTA interface that supports the following firmware sources:

1. GitHub Releases

• List available official firmware releases from the OpenEarable/open-earable-2 GitHub repository
• Allow the user to select a specific release version (e.g. v2.2.2)
• Download the corresponding signed firmware artifact(s) from the release assets

2. Pull Request / Pre-release Builds

• List and select firmware builds from the rolling pr-builds pre-release (or individual PR artifacts)
• Useful for testing in-progress features without building from source

3. Custom / Local Firmware File

• Accept a user-supplied .bin / .zip firmware file path or URL
• Validate the file before attempting the update

Acceptance Criteria

• The connector exposes a FOTA API (e.g. fota.fromRelease(version), fota.fromFile(path), fota.fromPR(prNumber))
• Firmware can be fetched from GitHub releases and PR pre-release builds via the GitHub API
• Users can provide a local firmware file for upload
• Progress and status of the update is reported back to the caller (e.g. percentage, success/failure)
• Error handling for connectivity issues, invalid firmware, or device rejections
• Documentation and at least one usage example are included