chore(release): v1.28.56 — documents, closer to hand

Bundles the documents/coach slices onto the daily-system release:
- Ask the Coach about a document opens in a side panel (expandable to full
  page), not a full-page jump.
- Attach one or more documents to a Coach chat from the composer (pick from the
  vault or upload); the conversation runs fenced — grounded in those documents
  only, no health data or tools — and can never reach the tool loop (a sticky
  document-scoped flag plus dual client/server enforcement; migration 0245).
- A read document that looks like lab work has its values detected and proposed
  for your labs, added only on your one-tap confirm.
- A lab scan is also filed in your vault (encrypted) and linked to the readings.

Adversarially security-reviewed (multi-document attach): all clear.

docs/api/openapi.yaml

@@ -1,7 +1,7 @@
 openapi: 3.1.0
 info:
   title: HealthLog API
-  version: 1.28.55
+  version: 1.28.56
   description: >-
     Self-hosted personal-health-tracking PWA — public API surface for the iOS native client and external ingest.