chore(release): v1.28.11 — Strava workouts + Garmin guidance

Adds a Strava connection (BYO app keys, per-user, mirroring the other
wearables): activities arrive as workouts, de-duplicated against other sources
by the existing source-priority picker, workouts-only. Documents that Garmin has
no direct connector and flows in via Apple Health / Google Health Connect.
Migration 0233; new MeasurementSource STRAVA on /api/sync/changes.

docs/api/openapi.yaml

@@ -1,7 +1,7 @@
 openapi: 3.1.0
 info:
   title: HealthLog API
-  version: 1.28.10
+  version: 1.28.11
   description: >-
     Self-hosted personal-health-tracking PWA — public API surface for the iOS native client and external ingest.