Add renderers for file watcher and heartbeat events

[pruiz]

The TUI/log output is currently showing several events as raw/unknown messages instead of being handled by specific renderers.

Observed in the screenshot:

unknown event type: file.watcher.updated
server heartbeat
server heartbeat
server heartbeat
unknown event type: file.edited
unknown event type: file.watcher.updated
server heartbeat
unknown event type: file.edited
unknown event type: file.watcher.updated
server heartbeat
server heartbeat
server heartbeat
server heartbeat

Scope

Add or fix the event renderers needed for at least:

• file.watcher.updated
• file.edited
• server heartbeat events

Expected behavior

• These events should no longer be emitted as unknown event type.
• Each event type should have an explicit renderer/handler, even if the initial rendering is intentionally compact.
• Heartbeat events should probably be rendered in a low-noise way, hidden by default, or routed to the status/heartbeat area instead of filling the main log.

Acceptance criteria

• Running the same flow no longer prints unknown event type: file.watcher.updated or unknown event type: file.edited.
• Heartbeat events do not spam the main output.
• Existing known event rendering remains unchanged.
• Add a small regression test covering these event types so future protocol additions are easy to spot.