fix(docker): drop unconditional RUNTIME_API_ORIGIN passthrough from compose

The line was injecting an empty string when the variable wasn't set in the
caller's environment, which the prior commit normalizes at the schema level.
Removing the passthrough closes the surface entirely (defense in depth) and
mirrors the Helm chart's conditional inclusion (`{{- with .Values... }}`).
Operators who want to set RUNTIME_API_ORIGIN follow the documented example
in .env.example, which is loaded by Docker Compose automatically and works
exactly like the other optional origin overrides.

Author: ThullyoCunha

hosting/docker/webapp/docker-compose.yml

@@ -43,7 +43,6 @@ services:
       APP_ORIGIN: ${APP_ORIGIN:-http://localhost:8030}
       LOGIN_ORIGIN: ${LOGIN_ORIGIN:-http://localhost:8030}
       API_ORIGIN: ${API_ORIGIN:-http://localhost:8030}
-      RUNTIME_API_ORIGIN: ${RUNTIME_API_ORIGIN:-}
       ELECTRIC_ORIGIN: http://electric:3000
       DATABASE_URL: ${DATABASE_URL:-postgresql://postgres:postgres@postgres:5432/main?schema=public&sslmode=disable}
       DIRECT_URL: ${DIRECT_URL:-postgresql://postgres:postgres@postgres:5432/main?schema=public&sslmode=disable}