Remove vestigial clickhouse.enabled flag

ClickHouse is the only storage backend — there is no alternative.
The enabled flag created a false sense of optionality: setting it to
false would crash on startup because most beans unconditionally depend
on the ClickHouse JdbcTemplate.

Remove all @ConditionalOnProperty annotations gating ClickHouse beans,
the enabled property from application.yml, and the K8s manifest entry.
Also fix old property names in AbstractPostgresIT test config.

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

deploy/base/server.yaml

@@ -70,8 +70,6 @@ spec:
                   name: cameleer-auth
                   key: CAMELEER_SERVER_SECURITY_JWTSECRET
                   optional: true
-            - name: CAMELEER_SERVER_CLICKHOUSE_ENABLED
-              value: "true"
             - name: CAMELEER_SERVER_CLICKHOUSE_URL
               value: "jdbc:clickhouse://clickhouse.cameleer.svc.cluster.local:8123/cameleer"
             - name: CAMELEER_SERVER_CLICKHOUSE_USERNAME