docs: add instrument-aware quote unit story

docs/roadmap/ROADMAP.yaml

@@ -12,6 +12,7 @@ notes:
   - Priority ordering is maintained here so agents can parse one short file first.
 priority_queue:
   - CORE-001D
+  - CORE-002
   - BT-003B
   - PORT-003
   - BT-002
@@ -42,6 +43,7 @@ states:
     - BT-003B
     - BT-001C
     - CORE-001D
+    - CORE-002
   in_progress: []
   done:
     - DATA-001

docs/roadmap/backlog/CORE-002-instrument-aware-quote-units.yaml

@@ -0,0 +1,23 @@
+id: CORE-002
+title: Instrument-Aware Quote Units and Conversion Multipliers
+status: backlog
+priority: P0
+effort: M
+depends_on:
+  - CORE-001A
+  - CORE-001B
+  - CORE-001C
+tags: [core, units, pricing, domain]
+summary: >
+  Model quoted instruments with explicit asset/share units and conversion multipliers
+  so prices like GLD are never misinterpreted as physical-gold ounce prices.
+acceptance_criteria:
+  - GLD quotes are modeled explicitly as prices per share, not as ambiguous gold-ounce prices.
+  - Instrument metadata encodes that 1 GLD share represents 0.1 troy ounces of gold exposure.
+  - Storage/domain value classes know the unit relationship and convert correctly when calculations combine instrument prices with ounce-based quantities.
+  - Cross-unit operations fail closed when no explicit instrument conversion path exists.
+  - Tests cover GLD share <-> troy-ounce conversion and reject unsupported mixed-unit operations.
+technical_notes:
+  - Prefer explicit instrument/unit types over ad hoc scale factors in page/service code.
+  - This should integrate with the Decimal/unit-safe domain model rather than bypass it with raw floats.
+  - Consider extending historical/unit types so both live overview paths and backtesting/event paths can share the same conversion rules.