feat(charts): extract shared chart-height and range-preset constants

New module src/lib/charts/constants.ts exports CHART_HEIGHT_PX (240),
CHART_MINI_HEIGHT_PX (160), and CHART_RANGE_PRESETS (7d / 30d / 90d / All).
The constants give the dashboard chart strip and the GLP-1 tile one
source of truth so future retuning lands in one place.

src/lib/charts/constants.ts

@@ -0,0 +1,42 @@
+/**
+ * Shared chart layout constants for the dashboard trend strip.
+ *
+ * Why a single module: prior to v1.4.27 the three chart files
+ * (`health-chart.tsx`, `mood-chart.tsx`, `medication-compliance-chart.tsx`)
+ * carried their own hard-coded heights, which drifted apart over time —
+ * MoodChart landed on 280 px while every other sibling rendered at 240 px,
+ * which broke the vertical rhythm of the trend strip. The constants
+ * below give every chart card one source of truth so a future maintainer
+ * can retune from one place.
+ *
+ * Heights are in CSS pixels. Tailwind arbitrary-value classes elsewhere
+ * read them as `h-[${CHART_HEIGHT_PX}px]`.
+ */
+
+/** Full-size trend-card body height (non-mini chart cards on the dashboard). */
+export const CHART_HEIGHT_PX = 240;
+
+/**
+ * Compact / mini variant used by inline previews (rationale cards,
+ * dashboard tile carve-outs). Smaller so the chart fits inside a host
+ * card without doubling its vertical footprint.
+ */
+export const CHART_MINI_HEIGHT_PX = 160;
+
+/**
+ * Range-preset options for charts that expose a 7d / 30d / 90d / All
+ * range selector. Each entry carries the i18n keys for the visible
+ * label + sr-only title, plus a `points` count used by the underlying
+ * `HealthChart` query window. `points: 0` denotes "all data".
+ *
+ * Re-used by the GLP-1 dashboard tile so its range strip stays in
+ * lockstep with the rest of the trend strip.
+ */
+export const CHART_RANGE_PRESETS = [
+  { labelKey: "charts.points7Label", titleKey: "charts.points7Title", points: 7 },
+  { labelKey: "charts.points30Label", titleKey: "charts.points30Title", points: 30 },
+  { labelKey: "charts.points90Label", titleKey: "charts.points90Title", points: 90 },
+  { labelKey: "charts.pointsAllLabel", titleKey: "charts.pointsAllTitle", points: 0 },
+] as const;
+
+export type ChartRangePreset = (typeof CHART_RANGE_PRESETS)[number];