Feat: Add default user account and consolidate account actions in menu (#1130)

* feat: Add default account for manual transaction entries (#1061)

Allow users to designate a default account that auto-selects
in the transaction creation form. Also consolidates account list
actions (edit, link/unlink, enable/disable) into a meatball menu.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* - handle context menu width on mobile
- restrict default account to depository types only
- added FR, ES and DE i18n files

* - Add credit card accounts can also be used as default
- Moved logic into controller

* Scope context menu max-width to accounts menu only
- decouples the width constraint from the shared DS::Menu component by introducing an optional max_width param

* fix ci test and address issues raised by coderabbit and codex

* Address CodeRabbit review feedback

- Use .present? for institution_name guards to avoid empty UI artifacts
- Align "Set default" menu visibility with actual preselection eligibility
  (active + unlinked + supports_default?) to prevent drift between UI and model
- Keep disabled star visible when account is already default but now ineligible

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* Add eligible_for_transaction_default? predicate to Account model

Consolidates active + unlinked + supports_default? checks into a single
shared predicate used by the controller, view, and user model guard,
preventing a direct PATCH from bypassing UI eligibility rules.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* Added "Unset default" option
Added negative test for default account
Removed duplicated logic for account.eligible_for_transaction_default

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

db/schema.rb

@@ -1474,6 +1474,8 @@ ActiveRecord::Schema[7.2].define(version: 2026_03_14_131357) do
     t.jsonb "preferences", default: {}, null: false
     t.string "locale"
     t.string "ui_layout"
+    t.uuid "default_account_id"
+    t.index ["default_account_id"], name: "index_users_on_default_account_id"
     t.index ["email"], name: "index_users_on_email", unique: true
     t.index ["family_id"], name: "index_users_on_family_id"
     t.index ["last_viewed_chat_id"], name: "index_users_on_last_viewed_chat_id"
@@ -1584,6 +1586,7 @@ ActiveRecord::Schema[7.2].define(version: 2026_03_14_131357) do
   add_foreign_key "transactions", "merchants"
   add_foreign_key "transfers", "transactions", column: "inflow_transaction_id", on_delete: :cascade
   add_foreign_key "transfers", "transactions", column: "outflow_transaction_id", on_delete: :cascade
+  add_foreign_key "users", "accounts", column: "default_account_id", on_delete: :nullify
   add_foreign_key "users", "chats", column: "last_viewed_chat_id"
   add_foreign_key "users", "families"
 end