Add WebSocket support for TrueNAS JSON-RPC 2.0 API

[jaycollett]

Summary

TrueNAS is deprecating the REST API (api/v2.0/) in version 26.04, requiring migration to JSON-RPC 2.0 over WebSocket. This PR adds the core WebSocket infrastructure needed to support TrueNAS CORE and SCALE apps.

Changes

• Add phrity/websocket dependency for WebSocket communication
• Add TrueNASWebSocketClient helper class that handles:
  • Connection to ws(s)://host/api/current
  • Authentication via auth.login_with_api_key
  • JSON-RPC 2.0 request/response formatting
  • TLS verification toggle
  • Proper connection cleanup

Technical Details

The WebSocket client uses the phrity/websocket v3.x library with proper SSL context configuration:

• Forces ALPN to HTTP/1.1 for WebSocket upgrade compatibility (TrueNAS nginx defaults to HTTP/2)
• Supports self-signed certificates when TLS verification is disabled

Companion PR

Depends on: linuxserver/Heimdall-Apps#889

This PR provides the core infrastructure. The TrueNAS app updates are in:

• Migrate TrueNAS apps to JSON-RPC 2.0 WebSocket API Heimdall-Apps#889 - Migrate TrueNAS apps to JSON-RPC 2.0 WebSocket API

Both PRs need to be merged for full functionality. Existing TrueNAS apps will continue to work with REST API until the companion PR is merged.

References

• Closes truenas app still use the deprecated REST API #1530
• TrueNAS JSON-RPC API Documentation

Backward Compatibility

TrueNAS Version	REST API	WebSocket	Notes
< 25.04	✅	❌	REST only
25.04	⚠️ Deprecated	✅	Both available
26.04+	❌ Removed	✅	WebSocket required

Test Plan

• Tested WebSocket connection with TrueNAS SCALE 25.10.1
• Verified authentication with API key
• Confirmed JSON-RPC 2.0 calls work (core.ping, system.info, alert.list)
• Tested with self-signed certificates (ignore_tls option)

[LinuxServer-CI]

This pull request has been automatically marked as stale because it has not had recent activity. This might be due to missing feedback from OP. It will be closed if no further activity occurs. Thank you for your contributions.

[Sunoo]

Please actually merge this.

[LinuxServer-CI]

This pull request has been automatically marked as stale because it has not had recent activity. This might be due to missing feedback from OP. It will be closed if no further activity occurs. Thank you for your contributions.

[Sunoo]

What needs to be done to get someone to review this? Is this project still maintained?

[j0nnymoe]

App changes need to be submitted here: https://github.com/linuxserver/heimdall-apps

This is still maintained but new features aren't really being added, the apps repo is monitored by a couple community users who are able to approve PR's.

[Sunoo]

It was submitted there, but it seems to require a change in both: linuxserver/Heimdall-Apps#889