V2: connected TUIs duplicate durable event logs #36283

Problem

Every connected V2 TUI receives the global SSE event stream and writes each durable event to the shared ~/.local/share/opencode/log/opencode.log file. The same event is therefore logged once per connected TUI.

During a next-15295 incident with seven connected TUIs, identical event records appeared under seven client run IDs with the same aggregate ID and sequence. One minute contained approximately 9,000 client-side durable-event log lines, and the shared log had grown to 477 MB.

Expected behavior

The number of identical durable-event records written to the shared text log should not scale with the number of connected TUI clients.