fix: let Flyway inherit datasource connection instead of separate URL

Explicit spring.flyway.url/user/password used SPRING_DATASOURCE_URL env
var but Flyway resolves its own defaults independently, falling back to
localhost when the env var mapping doesn't match. Removing the explicit
Flyway connection config lets it inherit from the datasource, which is
correctly configured.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/main/resources/application.yml

@@ -12,9 +12,6 @@ spring:
   flyway:
     enabled: true
     locations: classpath:db/migration
-    url: ${SPRING_DATASOURCE_URL:jdbc:postgresql://postgres:5432/cameleer_saas}
-    user: ${SPRING_DATASOURCE_USERNAME:cameleer}
-    password: ${SPRING_DATASOURCE_PASSWORD:cameleer_dev}
   security:
     oauth2:
       resourceserver: