Fix OpenAPS pill and forecast lines disappearing on missing rate field

[sergev-art]

Summary

Fixes an intermittent bug where the OpenAPS status pill stops updating and forecast lines vanish from the dashboard. Root cause: lastEnacted objects from certain OpenAPS configurations do not include a rate field, causing an unhandled reference error that crashes the plugin.

• Production code change: 1 line in lib/plugins/openaps.js — null-safe access to lastEnacted.rate
• Test coverage: New test file with real-world edge case data fixtures (2 JSON files capturing actual device status payloads)

Upstream: nightscout#8324

Design Control Impact

Modified Requirements

• OpenAPS plugin specification (SS-level): The plugin shall handle missing or undefined fields in lastEnacted device status objects without crashing
• Display continuity (SR-level): Forecast lines and status pills shall continue rendering when individual data fields are absent

New Test Cases

• openaps.missingPill.test.js: Verifies plugin renders correctly with lastEnacted missing rate field
• Test fixtures: missingRateOnLastEnacted.json, statusWithWorkingForecast.json

Risk Items

• Patient safety (HIGH): Disappearing forecast lines and stale OpenAPS status could lead a patient or caregiver to make incorrect treatment decisions based on missing information
• Silent failure: No error displayed to user — the pill and forecast simply stop updating, which may not be immediately noticed
• Data source variability: Different OpenAPS/AAPS versions produce different device status payloads — the plugin must be resilient to schema variations

Files Changed (4)

File	Change	Lines
lib/plugins/openaps.js	Null-safe access to lastEnacted.rate	+1/-1
tests/openaps.missingPill.test.js	New edge case test	+63/-0
tests/data/missingRateOnLastEnacted.json	Real-world test fixture	+117/-0
tests/data/statusWithWorkingForecast.json	Real-world test fixture	+121/-0