id: PORTFOLIO-002
title: Position Storage Costs
status: backlog
priority: P1
size: S
depends_on:
  - PORTFOLIO-001
tags: [portfolio, costs]
summary: Allow users to configure storage costs for portfolio positions.
acceptance_criteria:
  - Each position can have optional storage_cost_basis (annual % or fixed amount)
  - Storage cost period selectable: annual, monthly
  - Overview page shows aggregate storage cost impact on net equity
  - Hedge recommendations account for storage drag
  - Physical gold positions default to typical vault storage (e.g., 0.12% annual for allocated)
  - GLD positions note that expense ratio is already baked into price
notes:
  - For GLD: expense ratio decay is implicit, no separate storage cost needed
  - For GC=F: roll costs (contango) are the primary storage analog
  - For physical XAU: vault storage is explicit cost
  - Storage costs affect LTV calculations (reduce effective equity)
implementation_hints:
  - Add `storage_cost_basis: Decimal | None` to `Position`
  - Add `storage_cost_period: "annual" | "monthly" | None` to `Position`
  - Compute annualized storage cost for equity/P&L display
  - Add storage cost breakdown to overview page