docs: mark DATA-004 done, update roadmap

docs/roadmap/backlog/DATA-004-underlying-instrument-selector.yaml

@@ -1,25 +0,0 @@
-id: DATA-004
-title: Underlying Instrument Selector
-status: backlog
-priority: P2
-size: L
-depends_on:
-  - PRICING-001
-acceptance_criteria:
-  - User can choose underlying instrument for options evaluation (GLD vs GC=F)
-  - Settings page exposes underlying selector with brief descriptions
-  - Workspace-scoped preference persisted
-  - Overview and Hedge pages reflect chosen underlying for price display and options strategy
-  - GC=F options data source placeholder exists (not yet wired to live data)
-  - UI clearly indicates which underlying is active and whether data is live or placeholder
-notes:
-  - GLD is the MVP supported underlying with live data via yfinance
-  - GC=F futures options will require a new data source (future roadmap item)
-  - For now, GC=F selection can show "coming soon" or use estimated/stubbed pricing
-  - Each underlying has different contract specs (100 shares vs futures contract multiplier)
-implementation_hints:
-  - Add underlying field to workspace/portfolio settings
-  - Extend app/domain/instruments.py with GC=F metadata (futures contract specs)
-  - Add underlying selector UI in settings
-  - DataService routes quote/options requests based on selected underlying
-  - For GC=F, stub with estimated pricing or clear "data source needed" state