feat(savings_goals/index): collapsed Archived section + archived-aware card

- Controller: @archived_goals exposes state=archived rows already pulled
  by the all_goals load. No extra query (sliced from the existing array).
- Index template: <details> disclosure under "Completed" so archived
  goals are reachable from the list without cluttering the active /
  completed sections. Collapsed by default.
- GoalCardComponent: uses display_status for the data attribute (so the
  card on the index reads as Archived instead of Behind), opacity-75
  applies to archived too, footer_line short-circuits to "Archived" and
  pace_line returns nil. Matches the show-page archived semantics
  shipped earlier.
- Locale: new savings_goals.index.archived_section.heading and
  savings_goals.goal_card.footer_archived.

app/controllers/savings_goals_controller.rb

@@ -13,6 +13,7 @@ class SavingsGoalsController < ApplicationController
     @active_goals = all_goals.reject { |g| %w[completed archived].include?(g.state) }
                              .sort_by { |g| [ g.paused? ? 3 : ACTIVE_STATUS_RANK.fetch(g.status, 4), g.name.downcase ] }
     @completed_goals = all_goals.select { |g| g.state == "completed" }
+    @archived_goals = all_goals.select { |g| g.state == "archived" }
 
     @linkable_account_count = Current.family.accounts.where(accountable_type: "Depository").visible.count
     @kpi = kpi_payload(@active_goals)