id: PORTFOLIO-001
title: Position-Level Portfolio Entries
status: backlog
priority: P0
size: M
depends_on: []
tags: [portfolio, domain-model]
summary: Evolve from single-quantity portfolio to multi-position entries with individual entry dates and prices.
acceptance_criteria:
  - User can add a position entry with underlying type (GLD shares, GC=F contracts, XAU grams/oz)
  - Each position has its own entry_price, entry_date, quantity
  - Portfolio page shows list of positions with individual P&L
  - Portfolio total collateral is sum of all position values in display currency
  - Backward compatible: existing single-entry portfolios migrate to one position entry
  - Settings page has "Add Position" and "Remove Position" controls
  - Position CRUD persists to workspace storage
notes:
  - This is foundational for mode switching between GLD/GC=F/physical gold
  - Entry_date matters for conversion lookups (GLD backing varies by date)
  - Single-quantity legacy portfolios should auto-migrate to one position
implementation_hints:
  - Add `Position` dataclass in `app/models/portfolio.py`
  - Add `positions: List[Position]` to `PortfolioConfig` (migrate `gold_ounces`/`entry_price` to first position)
  - Position underlying defaults to "GLD" for backward compat
  - Entry_date defaults to position creation date if not specified
  - Storage costs deferred to PORTFOLIO-002