fix(automations): exclude paused accounts from the sweep so they can't starve others

Now that a flag-off account's due rows stay pending (paused), order(:due_at).limit
would keep re-selecting that backlog every sweep, starving enabled accounts with
later due_at. Filter the sweep to accounts with delayed_automations enabled via a
for_enabled_accounts scope, so paused rows sit out of the limit until re-enabled.

app/jobs/automation_rules/trigger_pending_executions_job.rb

@@ -9,7 +9,7 @@ class AutomationRules::TriggerPendingExecutionsJob < ApplicationJob
     started_at = Time.current
     purged = AutomationRulePendingExecution.purge_terminal!
 
-    rows = AutomationRulePendingExecution.sweepable.order(:due_at).limit(sweep_limit).to_a
+    rows = AutomationRulePendingExecution.sweepable.for_enabled_accounts.order(:due_at).limit(sweep_limit).to_a
     rows.each { |row| AutomationRules::ProcessPendingExecutionJob.perform_later(row) }
 
     log_summary(enqueued: rows.size, capped: rows.size >= sweep_limit, purged: purged, started_at: started_at)

app/models/automation_rule_pending_execution.rb

@@ -45,6 +45,10 @@ class AutomationRulePendingExecution < ApplicationRecord
   # Non-terminal rows still bound to fire (a stale processing row is reclaimed by the sweep).
   scope :armed, -> { where(status: [statuses[:pending], statuses[:processing]]) }
 
+  # Excludes rows whose account paused delayed automations, so one disabled account's backlog
+  # can't fill the sweep limit and starve enabled accounts (paused rows resume on re-enable).
+  scope :for_enabled_accounts, -> { joins(:account).merge(Account.feature_delayed_automations) }
+
   def self.schedule(rule:, conversation:, message: nil)
     key = arm_episode_key_for(conversation, message)
     create!(