chore(license): move to PolyForm Noncommercial 1.0.0

The project licence changes from AGPL-3.0 to the PolyForm Noncommercial
License 1.0.0 for this and future versions: free to use, modify and
self-host for noncommercial purposes; commercial use needs a separate
arrangement. Releases up to and including v1.15.18 were published under
AGPL-3.0 and remain available under that licence. LICENSE carries the
verbatim PolyForm text, and the SPDX identifier is updated in
package.json, the version endpoint, the OpenAPI info block, the image
labels and the README.

docs/api/openapi.yaml

@@ -15,14 +15,14 @@ info:
     Background-job-authored payloads (backups, admin tools) emit `Z`. Native iOS clients should always parse via a
     Foundation ISO-8601 formatter with the `withInternetDateTime` + `withTimeZone` options enabled.
   license:
-    name: AGPL-3.0
+    name: PolyForm-Noncommercial-1.0.0
     url: https://github.com/MBombeck/HealthLog/blob/main/LICENSE
   contact:
     name: HealthLog
     url: https://healthlog.dev
 servers:
-  - url: https://healthlog.bombeck.io
-    description: Production
+  - url: https://healthlog.example.com
+    description: Your self-hosted instance
   - url: http://localhost:3000
     description: Local dev
 tags: