Pre-existing format drift accumulated across v1.4.x; running
prettier brings the whole tree back to baseline so future diffs
read clean. No behaviour change.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Add a `compareBaseline` prop to HealthChart and MoodChart that, when
set to "lastMonth" or "lastYear", overlays the prior-period series as
a dimmed dashed line beneath the current data. The shift is computed
in-memory by `shiftDailySeriesForward` — the chart already fetches the
full measurement history so no extra API call is needed.
The tooltip switches its delta line from "vs. your normal" to "vs. last
month / last year" when comparison is active and a prior value exists
for the hovered day, and adds a second row with the prior absolute
value so both numbers are visible. The chart header gains a
"vs. last month / last year" caption (or an "unavailable — no data
yet" fallback when the prior period has no overlap).
The dashboard page and the insights page both read the persisted
preference from `User.dashboardWidgetsJson.comparisonBaseline` so a
single toggle flip in Settings → Dashboard updates every chart on
both surfaces atomically.
Pure shift helper lives at `src/lib/charts/comparison-shift.ts` with
11 unit tests pinning the day-exact forward shift, the average helper,
and the delta computation (null-safe).
Regression guard: when comparisonBaseline is "none" (default), the
chart renders exactly as before — no extra paint, no caption, no
tooltip change.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
