chore(release): v1.35.3 — an ECG arrives on its own, and only once

Apple Watch ECG recordings reach the record straight from the app instead of
only through an export archive. One recording per request, gated by the same
switches that already govern reading them.

A recording is now identified by what it is rather than by what a source calls
it, so the same strip arriving through both doors converges on one row. The
migration that adds the constraint resolves the duplicates already stored: it
keeps the row holding the waveform over one holding only a verdict, and moves a
removed row's event link onto the row that is kept. The losing rows are deleted.

docs/api/openapi.yaml

@@ -1,7 +1,7 @@
 openapi: 3.1.0
 info:
   title: HealthLog API
-  version: 1.35.2
+  version: 1.35.3
   description: >-
     Self-hosted personal-health-tracking PWA — public API surface for the iOS native client and external ingest.