com_r35157_nenjim-hubd-impl_ref/openspec/changes/archive/2026-08-05-59-add-evelyn-status-index-chart/tasks.md

1. Typed Status History

• 1.1 Add the immutable EvelynStatusIndexPoint API value type with an Instant timestamp and six named BigDecimal index values.
• 1.2 Replace Evelyn.getStatusReport() with the non-null getStatusIndexHistory() list contract.
• 1.3 Implement an immutable, oldest-to-newest hardcoded sample history in EvelynImpl.

2. Mission Control Overview

• 2.1 Update Mission Control to accept separate Production and Test Evelyn references and fetch each reference's history for its corresponding Overview tab.
• 2.2 Update NenjimHub to supply two separate EvelynImpl placeholder instances and keep distinct six-series chart instances for the two histories.
• 2.3 Configure a dynamic symmetric Y-axis around zero, including a usable zero-containing fallback range for empty or all-zero history.

3. Verification

• 3.1 Compile the project and manually confirm each Overview tab renders its corresponding Evelyn history in a separate chart without adding automated tests.