feat(settings): a time-format preference and one home for insight pills

The clock format followed the UI language with no way out — an English
interface forced AM/PM everywhere. A new profile preference (automatic,
24-hour, 12-hour) feeds every formatter through the shared locale
context, persists on the user row and rides the profile endpoints. The
insight pill list in settings gains the same eye toggle the overview
tiles have, so ordering and visibility live in one place; the page-side
'manage detail pages' block folds into a link there. Includes the
locale bundles for both features and the regenerated API contract.

docs/api/openapi.yaml

@@ -4615,6 +4615,13 @@ components:
           type: string
           minLength: 1
           maxLength: 64
+        timeFormat:
+          description: Hour-cycle display preference. AUTO follows the locale convention, H12 forces AM/PM, H24 forces 24-hour.
+          type: string
+          enum:
+            - AUTO
+            - H12
+            - H24
         moodReminderEnabled:
           type: boolean
         fullName:
@@ -10022,6 +10029,13 @@ components:
             - type: "null"
         timezone:
           type: string
+        timeFormat:
+          type: string
+          enum:
+            - AUTO
+            - H12
+            - H24
+          description: Hour-cycle display preference. AUTO follows the locale convention, H12 forces AM/PM, H24 forces 24-hour.
         moodReminderEnabled:
           type: boolean
         fullName:
@@ -10050,6 +10064,7 @@ components:
         - heightCm
         - locale
         - timezone
+        - timeFormat
         - moodReminderEnabled
         - fullName
         - insurerName
@@ -10111,6 +10126,13 @@ components:
             - type: "null"
         timezone:
           type: string
+        timeFormat:
+          type: string
+          enum:
+            - AUTO
+            - H12
+            - H24
+          description: Hour-cycle display preference. AUTO follows the locale convention, H12 forces AM/PM, H24 forces 24-hour.
         moodReminderEnabled:
           type: boolean
         fullName:
@@ -10137,6 +10159,7 @@ components:
         - heightCm
         - locale
         - timezone
+        - timeFormat
         - moodReminderEnabled
         - fullName
         - insurerName
@@ -10668,10 +10691,16 @@ components:
             - ready
             - preparing
             - disabled
+            - no-provider
         briefingUpdatedAt:
           anyOf:
             - type: string
             - type: "null"
+        briefingStale:
+          type: boolean
+          description: True when `briefing` carries the last good (expired-TTL) briefing while a refresh is pending (`preparing`)
+            or impossible (`no-provider`). Render the stale content with its `briefingUpdatedAt` timestamp instead of a
+            blank tile.
         generatedAt:
           type: string
       required:
@@ -10684,15 +10713,18 @@ components:
         - briefing
         - briefingState
         - briefingUpdatedAt
+        - briefingStale
         - generatedAt
       additionalProperties: false
-      description: Unified above-the-fold dashboard payload. `tiles` always arrives (slim summaries + mood + resolved widget
+      description: "Unified above-the-fold dashboard payload. `tiles` always arrives (slim summaries + mood + resolved widget
         layout); `extras` (BD-in-target + per-context glucose) is null on a rollup-coverage miss so the strip never
         waits on the slowest read. `briefing` is lifted read-only from the pre-generated insight cache — never generated
-        synchronously — and reports `ready` / `preparing` / `disabled` via `briefingState`. `layoutCatalogue` (full
-        27-id widget catalogue) and `metricStates` (latest reading per metric, keyed by iOS `MetricKind` raw value) are
-        additive cold-launch seeds for the native client; both derive in-process from data already fetched, adding no DB
-        round-trip.
+        synchronously — and reports `ready` / `preparing` / `disabled` / `no-provider` via `briefingState`
+        (`no-provider` = stale-or-missing cache with no AI provider configured anywhere, so no warm pass will fill it;
+        stop polling and surface a connect-provider hint). A stale-but-parseable briefing is still delivered with
+        `briefingStale: true`. `layoutCatalogue` (full 27-id widget catalogue) and `metricStates` (latest reading per
+        metric, keyed by iOS `MetricKind` raw value) are additive cold-launch seeds for the native client; both derive
+        in-process from data already fetched, adding no DB round-trip."
     InsightsComprehensiveResponseEnvelope:
       type: object
       properties: