chore(release): v1.28.0 — document intelligence

Marks the document line as one coherent milestone: the vault becomes a
place to understand files, not just store them — read, indexed, searched,
shared, and answered — with a local-first / consented AI posture and a
vendor-blind egress notice held at every step. Ships alongside a full
correctness, resilience, and quality sweep down to the low-priority findings.

docs/api/openapi.yaml

@@ -1,7 +1,7 @@
 openapi: 3.1.0
 info:
   title: HealthLog API
-  version: 1.27.33
+  version: 1.28.0
   description: >-
     Self-hosted personal-health-tracking PWA — public API surface for the iOS native client and external ingest.