feat(measurements): wire walking-steadiness + audio-exposure-event through every registry

v1.4.30 commit 7 follow-up. The new MeasurementType values land in
every derived registry the canonical enum drives:

  - measurement-list-meta.ts label keys + icons + colors so the
    measurements list view renders both types (Gauge for steadiness,
    Volume2 for the loud-listening event)
  - 6 locale files (de/en/es/fr/it/pl) carry typeWalkingSteadiness +
    typeAudioExposureEvent keys; English-fallback copy for the four
    non-EN/DE locales matches the existing v1.4.25 W8d pattern
  - chart-tokens.ts ALLOWED_CHART_TOKENS list so the LLM can
    reference `metric:WALKING_STEADINESS` + `metric:AUDIO_EXPOSURE_EVENT`
    in prose; dedicated chart components ship alongside the iOS sync
  - the enum-coverage drift-guard test's EXPECTED_TYPES + PDF
    exclusion set so the canonical enum-extension lint stays green

Full unit suite passes (4035 specs).

src/components/measurements/measurement-list-meta.ts

@@ -68,6 +68,9 @@ export const MEASUREMENT_TYPE_LABEL_KEYS: Record<string, string> = {
   AUDIO_EXPOSURE_ENV: "measurements.typeAudioExposureEnv",
   AUDIO_EXPOSURE_HEADPHONE: "measurements.typeAudioExposureHeadphone",
   TIME_IN_DAYLIGHT: "measurements.typeTimeInDaylight",
+  // ── v1.4.30 R-F T1.4 + T1.5 ──
+  WALKING_STEADINESS: "measurements.typeWalkingSteadiness",
+  AUDIO_EXPOSURE_EVENT: "measurements.typeAudioExposureEvent",
 };
 
 export const MEASUREMENT_TYPE_ICONS: Record<string, LucideIcon> = {
@@ -110,6 +113,12 @@ export const MEASUREMENT_TYPE_ICONS: Record<string, LucideIcon> = {
   AUDIO_EXPOSURE_ENV: Volume2,
   AUDIO_EXPOSURE_HEADPHONE: Headphones,
   TIME_IN_DAYLIGHT: Sun,
+  // ── v1.4.30 R-F T1.4 + T1.5 ──
+  // Activity/Gauge carries the mobility-steadiness signal (same
+  // family as VO2_MAX). Volume2 is reused for the loud-listening
+  // event flag — the event is a louder-cousin of the env quantity.
+  WALKING_STEADINESS: Gauge,
+  AUDIO_EXPOSURE_EVENT: Volume2,
 };
 
 export const MEASUREMENT_TYPE_COLORS: Record<string, string> = {
@@ -149,4 +158,7 @@ export const MEASUREMENT_TYPE_COLORS: Record<string, string> = {
   AUDIO_EXPOSURE_ENV: "bg-chart-5/20 text-chart-5",
   AUDIO_EXPOSURE_HEADPHONE: "bg-chart-5/20 text-chart-5",
   TIME_IN_DAYLIGHT: "bg-chart-2/20 text-chart-2",
+  // ── v1.4.30 R-F T1.4 + T1.5 ──
+  WALKING_STEADINESS: "bg-chart-2/20 text-chart-2",
+  AUDIO_EXPOSURE_EVENT: "bg-chart-5/20 text-chart-5",
 };