id: DATA-DB-007
title: Databento GC Contract Mapping for Backtests
status: backlog
priority: P1
effort: M
depends_on:
  - DATA-DB-001
tags:
  - databento
  - futures
  - backtests
summary: Add real Databento futures contract mapping for GC backtests so the page can support gold futures without fail-closed restrictions.
acceptance_criteria:
  - Backtest-page Databento runs support GC without requiring users to know raw contract symbols.
  - Contract selection or front-month rollover rules are explicit and test-covered.
  - The selected contract path yields non-empty historical price data for supported windows.
  - Browser validation confirms the GC path works from `/{workspace_id}/backtests` with no visible runtime error.
technical_notes:
  - Current hardening work intentionally fail-closes GC on the backtest page because the raw `GC` symbol does not resolve reliably in Databento historical requests.
  - Follow-up work should decide between explicit contract selection, continuous mapping, or deterministic rollover logic before re-enabling GC in the Databento path.