perf(event_manager): Ignore server.heartbeat events

These events were triggering event flush every 40ms

Even if there was no streaming events. This should avoid refreshing the
output pane periodically when trying to keep the scrolling in sync

Author: sudo-tee

lua/opencode/event_manager.lua

@@ -183,6 +183,7 @@ local log = require('opencode.log')
 --- @field state_cwd_listener function|nil Listener for state.current_cwd updates
 --- @field is_started boolean Whether the event manager is started
 --- @field captured_events table[] List of captured events for debugging
+--- @field ignored_events string[] List of event types to ignore when capturing
 --- @field throttling_emitter ThrottlingEmitter Throttle instance for batching events
 local EventManager = {}
 EventManager.__index = EventManager
@@ -197,6 +198,7 @@ function EventManager.new()
     state_cwd_listener = nil,
     is_started = false,
     captured_events = {},
+    ignored_events = { 'server.heartbeat' },
     _parts_by_id = {},
   }, EventManager)
 
@@ -553,6 +555,14 @@ function EventManager:_subscribe_to_server_events(server)
   local api_client = state.api_client
 
   local emitter = function(event)
+    if not event or not event.type then
+      log.warn('Received malformed event from server: %s', vim.inspect(event))
+      return
+    end
+    if self.ignored_events and vim.tbl_contains(self.ignored_events, event.type) then
+      log.debug('Ignoring event of type %s', event.type)
+      return
+    end
     self.throttling_emitter:enqueue(event)
   end