fix: usage events never flushed to ClickHouse

UsageFlushScheduler was a @Component with @ConditionalOnBean, but
ClickHouseUsageTracker is created via @Bean — component scan runs
first, so the condition always evaluated false. Events accumulated
in the WriteBuffer but flush() was never called.

Moved scheduler to @Bean in StorageBeanConfig with the same
@ConditionalOnProperty guard as the tracker.

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

cameleer3-server-app/src/main/java/com/cameleer3/server/app/analytics/UsageFlushScheduler.java

@@ -3,12 +3,8 @@ package com.cameleer3.server.app.analytics;
 import com.cameleer3.server.app.storage.ClickHouseUsageTracker;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.scheduling.annotation.Scheduled;
-import org.springframework.stereotype.Component;
 
-@Component
-@ConditionalOnBean(ClickHouseUsageTracker.class)
 public class UsageFlushScheduler {
 
     private static final Logger log = LoggerFactory.getLogger(UsageFlushScheduler.class);

cameleer3-server-app/src/main/java/com/cameleer3/server/app/config/StorageBeanConfig.java

@@ -157,4 +157,11 @@ public class StorageBeanConfig {
             ClickHouseUsageTracker usageTracker) {
         return new com.cameleer3.server.app.analytics.UsageTrackingInterceptor(usageTracker);
     }
+
+    @Bean
+    @ConditionalOnProperty(name = "clickhouse.enabled", havingValue = "true")
+    public com.cameleer3.server.app.analytics.UsageFlushScheduler usageFlushScheduler(
+            ClickHouseUsageTracker usageTracker) {
+        return new com.cameleer3.server.app.analytics.UsageFlushScheduler(usageTracker);
+    }
 }