fix: standardize log prefixes, remove duplicates, add missing module tags

Second-pass logging cleanup: consistent [LEVEL] [module] format across
all 41 files. Remove stale prefixes ([CF], [SYNC], [SCHED], [API],
[STORAGE], [HEALTH], [ROLLBACK]). Remove 5 duplicate log lines. Gate
ungated DEBUG lines. Fix wrong log levels (restore start WARN→INFO).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

controller/internal/metrics/collector.go

@@ -69,12 +69,12 @@ func (c *MetricsCollector) loop(ctx context.Context) {
 func (c *MetricsCollector) sampleWith(ctx context.Context) {
 	sys := c.sampleSystem()
 	if err := c.store.InsertSystemMetrics(sys); err != nil {
-		c.logger.Printf("[WARN] Failed to store system metrics: %v", err)
+		c.logger.Printf("[WARN] [metrics] Failed to store system metrics: %v", err)
 	}
 
 	containers := c.sampleContainers(ctx)
 	if err := c.store.InsertContainerMetrics(containers); err != nil {
-		c.logger.Printf("[WARN] Failed to store container metrics: %v", err)
+		c.logger.Printf("[WARN] [metrics] Failed to store container metrics: %v", err)
 	}
 }
 
@@ -104,7 +104,7 @@ func (c *MetricsCollector) sampleContainers(parentCtx context.Context) []Contain
 		"--format", "{{.Name}}\t{{.CPUPerc}}\t{{.MemUsage}}\t{{.NetIO}}\t{{.BlockIO}}")
 	out, err := cmd.Output()
 	if err != nil {
-		c.logger.Printf("[WARN] docker stats failed: %v", err)
+		c.logger.Printf("[WARN] [metrics] docker stats failed: %v", err)
 		return nil
 	}