feat(integrations): say where an imported Google Health history ends

The two status routes publish backfillEnded: each data type whose
backfill stopped short of the start of its history, with the instant it
reaches back to and whether the horizon or a walk that stopped moving
ended it. The integration card lists them in place of an import that
would otherwise read as still loading, in all seven locales.

Refs #1220

docs/api/openapi.yaml

@@ -77868,6 +77868,34 @@ components:
           anyOf:
             - $ref: "#/components/schemas/ConnectionHealth"
             - type: "null"
+        backfillEnded:
+          type: array
+          items:
+            type: object
+            properties:
+              type:
+                type: string
+                description: The measurement type whose imported history ends here (e.g. `PULSE` for heart rate).
+              endsAt:
+                type: string
+                format: date-time
+                pattern: ^(?:(?:\d\d[2468][048]|\d\d[13579][26]|\d\d0[48]|[02468][048]00|[13579][26]00)-02-29|\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\d|30)|(?:02)-(?:0[1-9]|1\d|2[0-8])))T(?:(?:[01]\d|2[0-3]):[0-5]\d:[0-5]\d(?:\.\d+)?(?:Z|([+-](?:[01]\d|2[0-3]):[0-5]\d)))$
+                description: The oldest instant the imported history of this type reaches back to.
+              reason:
+                type: string
+                enum:
+                  - horizon
+                  - no_progress
+                description: "`horizon`: the backfill reads back a set number of years (`GOOGLE_HEALTH_BACKFILL_HORIZON_YEARS`, twenty
+                  by default) and the history goes further. `no_progress`: Google kept returning pages that reached no
+                  further back, so the import stopped there."
+            required:
+              - type
+              - endsAt
+              - reason
+            additionalProperties: false
+          description: Data types whose history backfill ended before the beginning of their history, with where and why. Empty
+            when every type was read to its start. Kept after the backfill completes; cleared on reconnect.
         needsReauth:
           deprecated: true
           description: "Deprecated: removed in v1.44, read `health`. The stored refresh token was rejected with `invalid_grant` —
@@ -78590,6 +78618,34 @@ components:
           type:
             - boolean
             - "null"
+        backfillEnded:
+          description: Google Health only. Data types whose history backfill ended before the beginning of their history, with
+            where and why.
+          type: array
+          items:
+            type: object
+            properties:
+              type:
+                type: string
+                description: The measurement type whose imported history ends here (e.g. `PULSE` for heart rate).
+              endsAt:
+                type: string
+                format: date-time
+                pattern: ^(?:(?:\d\d[2468][048]|\d\d[13579][26]|\d\d0[48]|[02468][048]00|[13579][26]00)-02-29|\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\d|30)|(?:02)-(?:0[1-9]|1\d|2[0-8])))T(?:(?:[01]\d|2[0-3]):[0-5]\d:[0-5]\d(?:\.\d+)?(?:Z|([+-](?:[01]\d|2[0-3]):[0-5]\d)))$
+                description: The oldest instant the imported history of this type reaches back to.
+              reason:
+                type: string
+                enum:
+                  - horizon
+                  - no_progress
+                description: "`horizon`: the backfill reads back a set number of years (`GOOGLE_HEALTH_BACKFILL_HORIZON_YEARS`, twenty
+                  by default) and the history goes further. `no_progress`: Google kept returning pages that reached no
+                  further back, so the import stopped there."
+            required:
+              - type
+              - endsAt
+              - reason
+            additionalProperties: false
         scope:
           description: Withings only.
           type: