chore(release): v1.21.2.1

Hotfix: the Coach and daily briefing failed for ChatGPT-provider accounts —
a provider tool-call rejection surfaced as a 500. Provider failures now
degrade gracefully, the Codex tool-call wire format is corrected, and the
provider error body is captured for diagnosis. Also: the thinking bubble
shows only the animated dots.

docs/api/openapi.yaml

@@ -1,7 +1,7 @@
 openapi: 3.1.0
 info:
   title: HealthLog API
-  version: 1.21.2
+  version: 1.21.2.1
   description: >-
     Self-hosted personal-health-tracking PWA — public API surface for the iOS native client and external ingest.