Open a Server-Sent Events stream of realtime application events

Opens an SSE connection that streams the application's realtime feed (deploy progress, status changes, live metrics, log lines) for up to 10 minutes per connection. Each user is limited to 5 concurrent realtime connections, and each application to 30 across all users.

The stream emits these event types:

• event: system carries protocol-level signals; the data: line is a single uppercase code: REALTIME_CONNECTING | <sseId> on connect, then any of REALTIME_TIMEOUT, REALTIME_DISCONNECTED, REALTIME_RECONNECT, REALTIME_ERROR.
• event: logs is a single log line whose FIRST character is a stream-id byte: \u0001 (stdout) or \u0002 (stderr). Read data.charCodeAt(0) (1 = stdout, 2 = stderr), then data.slice(1) for the line text. A line without that prefix byte is stdout.
• event: status carries live container metrics as a JSON string, about one frame per second. The FIRST frame of each (re)connection is COMPLETE: { cpu, cpuLimit, ram: [usedMB, limitMB], status, netIO: { i, o, new: { i, o } }, bIO: { i, o }, uptime } (uptime is StartedAt as epoch ms; netIO.new is bytes per second). Every later frame is LEAN, carrying only the live fields { cpu, ram, netIO, bIO }: the run-constant fields (cpuLimit, status, uptime) are omitted, so MERGE each lean frame onto the last full frame and keep the previous values for the missing fields. While this stream is open, prefer it over polling GET /v2/apps/:appId/status, which can be up to about a minute stale for an application with an open realtime stream.
• event: error carries an error code such as CONTAINER_NOT_FOUND.

Shapes vary by event, so parse structured payloads (the status JSON and most system/app messages) defensively and merge successive status frames.