Addresses Codex P2 on #2044. A Goal::Retirement row lives in
Current.family.goals, so the shared GoalsController and
GoalPledgesController loaded it through `family.goals.find(...)` —
never calling Goal::Retirement#editable_by?. Any preview-enabled
family member could therefore open /goals/:id and edit/archive/delete
another member's owner-scoped retirement plan, hit its pledge routes,
and see it listed in the savings Goals grid.
Adds `Goal.savings` (base type only) and scopes both savings
controllers to it, so retirement goals are unreachable through the
shared routes (RecordNotFound -> goals_path redirect) and absent from
the savings index. Owner-only retirement access stays in
RetirementController; editable_by? is retained for it.
Tests: savings scope excludes retirement; retirement goal absent from
goals index; show + pledge routes redirect not-found for retirement.
(The Codex schema.rb null:false finding is a false positive — this
branch's schema.rb retains null:false on all IBKR payload columns and
the diff vs the base branch touches no IBKR lines; Codex compared
against main rather than the PR base.)
839d6b36ad