feat(telemetry): add per-app metrics and log telemetry to hub reports (v0.28.0)

- New internal/metrics/telemetry.go: MetricsStore.GetContainerTelemetry()
  aggregates container memory/CPU from SQLite over the last 15 min
- New internal/metrics/logscanner.go: ScanContainerLogs() scans docker logs
  for errors/warnings, deduplicates via fingerprinting (strips timestamps,
  replaces 6+ digit numbers, hex strings, UUIDs)
- New internal/report/telemetry.go: buildAppTelemetrySection() assembles
  per-stack AppTelemetry by aggregating container metrics and log summaries
- internal/report/types.go: added AppTelemetry field to Report struct plus
  AppTelemetry type with memory/CPU/log fields and LogIssue references
- internal/report/builder.go: calls buildAppTelemetrySection() in BuildReport()
- Backward-compatible: old Hub versions silently ignore app_telemetry field

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

controller/internal/metrics/telemetry.go

@@ -0,0 +1,66 @@
+package metrics
+
+import (
+	"time"
+)
+
+// ContainerTelemetry holds aggregated resource stats for one container.
+type ContainerTelemetry struct {
+	ContainerName   string  `json:"container_name"`
+	MemoryCurrentMB float64 `json:"memory_current_mb"`
+	MemoryAvgMB     float64 `json:"memory_avg_mb"`
+	MemoryPeakMB    float64 `json:"memory_peak_mb"`
+	CPUAvgPercent   float64 `json:"cpu_avg_percent"`
+	SampleCount     int     `json:"sample_count"`
+}
+
+// GetContainerTelemetry queries the metrics DB for per-container resource
+// summaries since the given time. Returns empty slice (not error) if no data.
+func (s *MetricsStore) GetContainerTelemetry(since time.Time) ([]ContainerTelemetry, error) {
+	sinceUnix := since.Unix()
+
+	rows, err := s.db.Query(`
+		SELECT container_name,
+		       AVG(mem_usage_mb),
+		       MAX(mem_usage_mb),
+		       AVG(cpu_percent),
+		       COUNT(*)
+		FROM container_metrics
+		WHERE ts > ?
+		GROUP BY container_name`, sinceUnix)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var results []ContainerTelemetry
+	for rows.Next() {
+		var ct ContainerTelemetry
+		if err := rows.Scan(&ct.ContainerName, &ct.MemoryAvgMB, &ct.MemoryPeakMB,
+			&ct.CPUAvgPercent, &ct.SampleCount); err != nil {
+			continue
+		}
+		results = append(results, ct)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+
+	// Get current (most recent) memory per container
+	if stats, err := s.QueryContainerSummary(); err == nil {
+		currentMap := make(map[string]float64, len(stats))
+		for _, st := range stats {
+			currentMap[st.ContainerName] = st.MemUsageMB
+		}
+		for i := range results {
+			if cur, ok := currentMap[results[i].ContainerName]; ok {
+				results[i].MemoryCurrentMB = cur
+			}
+		}
+	}
+
+	if results == nil {
+		results = []ContainerTelemetry{}
+	}
+	return results, nil
+}