Balance sheet cache layer, non-blocking sync UI (#2356)

* Balance sheet cache layer with cache-busting

* Update family cache timestamps during Sync

* Less blocking sync loaders

* Consolidate family data caching key logic

* Fix turbo stream broadcasts

* Remove dev delay

* Add back account group sorting

app/models/family.rb

@@ -35,25 +35,6 @@ class Family < ApplicationRecord
   validates :locale, inclusion: { in: I18n.available_locales.map(&:to_s) }
   validates :date_format, inclusion: { in: DATE_FORMATS.map(&:last) }
 
-  # If any accounts or plaid items are syncing, the family is also syncing, even if a formal "Family Sync" is not running.
-  def syncing?
-    # Check for any in-progress syncs that belong directly to the family, to one of the
-    # family's accounts, or to one of the family's Plaid items. By moving the `visible`
-    # scope to the beginning we narrow down the candidate rows **before** performing the
-    # joins and by explicitly constraining the `syncable_type` for the direct Family
-    # match we allow Postgres to use the composite index on `(syncable_type, syncable_id)`.
-    Sync.visible
-        .joins("LEFT JOIN accounts ON accounts.id = syncs.syncable_id AND syncs.syncable_type = 'Account'")
-        .joins("LEFT JOIN plaid_items ON plaid_items.id = syncs.syncable_id AND syncs.syncable_type = 'PlaidItem'")
-        .where(
-          "(syncs.syncable_type = 'Family' AND syncs.syncable_id = :family_id) OR " \
-          "accounts.family_id = :family_id OR " \
-          "plaid_items.family_id = :family_id",
-          family_id: id
-        )
-        .exists?
-  end
-
   def assigned_merchants
     merchant_ids = transactions.where.not(merchant_id: nil).pluck(:merchant_id).uniq
     Merchant.where(id: merchant_ids)
@@ -110,13 +91,15 @@ class Family < ApplicationRecord
     entries.order(:date).first&.date || Date.current
   end
 
-  # Cache key that is invalidated when any of the family's entries are updated (which affect rollups and other calculations)
-  def build_cache_key(key)
+  def build_cache_key(key, invalidate_on_data_updates: false)
+    # Our data sync process updates this timestamp whenever any family account successfully completes a data update.
+    # By including it in the cache key, we can expire caches every time family account data changes.
+    data_invalidation_key = invalidate_on_data_updates ? latest_sync_completed_at : nil
+
     [
-      "family",
       id,
       key,
-      entries.maximum(:updated_at)
+      data_invalidation_key
     ].compact.join("_")
   end