Persistent connections (WebSockets/SSE)

[fabianabarca]

Description

Maintain connections with reconnection and heartbeats.

Acceptance Criteria

• WebSockets/SSE with exponential backoff
• Heartbeat protocol and timeouts
• Load/latency measured

[fabianabarca]

Tracked in #1

[gonguma]

Starts: 2025-10-11
Ends: 2025-10-21
Depends on: #2. Devices and groups must be registered to establish WebSocket/SSE connections. Additionally, the layout templates may influence how these connections interact on the frontend.