Split UI (#1245)

* Initial split transaction support

* Add support to unsplit and edit split

* Update show.html.erb

* FIX address reviews

* Improve UX

* Update show.html.erb

* Reviews

* Update edit.html.erb

* Add parent category to dialog

* Update en.yml

* Add UI indication to totals

* FIX ui update

* Add category select like rest of app

* Add split ui

* Add settings configuration for split transactions

- Adds a new settings section for appearance changes
- Also adds extra checks for delete and API calls
- Also adds checks for parent/child changes

* fixes

- split transactions dark mode fix
- add split transactions to context menu

* Update entry.rb

1. New validation split_child_date_matches_parent — prevents saving a split child with a date different from its parent. This is the root-cause fix that
   protects all flows at once.
  2. Bulk update guard — bulk_update! now strips :date from attributes when processing split children, preventing the validation from raising and silently
   skipping the date change instead.

* N+1 fix for split_parent?

* Update entry.rb

  Problem: In bulk_update!, when a split child has :date removed from attrs (line 432) and the remaining attrs is empty (e.g., the bulk update only
  changed the date), entry.update! {} still ran as a no-op. But lock_saved_attributes! and mark_user_modified! at lines 443-444 executed unconditionally,
  incorrectly marking untouched split children as user-modified and opting them out of future syncs.

  Fix:
  1. Added a changed flag to track whether any actual modification happened
  2. Wrapped entry.update! in an if attrs.present? check so no-op updates are skipped
  3. Gated lock_saved_attributes! and mark_user_modified! behind if changed, so they only run when the entry was actually modified (either via attribute
  update or tag update)

* fixes

1. Indentation in show.html.erb Settings section — The split button block and delete block had extra indentation making them appear nested inside guard
  blocks they weren't part of. Fixed to match actual nesting.
  2. Skip @split_parents query when grouping is off — The controller now only loads split parent entries when show_split_grouped? is true, saving a query
  with joins when the feature is disabled.

app/views/settings/_settings_nav.html.erb

@@ -6,6 +6,7 @@ nav_sections = [
       { label: t(".accounts_label"), path: accounts_path, icon: "layers" },
       { label: t(".bank_sync_label"), path: settings_bank_sync_path, icon: "banknote" },
       { label: t(".preferences_label"), path: settings_preferences_path, icon: "bolt" },
+      { label: t(".appearance_label"), path: settings_appearance_path, icon: "palette" },
       { label: t(".profile_label"), path: settings_profile_path, icon: "circle-user" },
       { label: t(".security_label"), path: settings_security_path, icon: "shield-check" },
       { label: t(".payment_label"), path: settings_payment_path, icon: "circle-dollar-sign", if: !self_hosted? && Current.family.can_manage_subscription? }