Refactor code structure and optimize performance across multiple modules

devops/offline/fixtures/telemetry/dashboards/ledger/alerts.yml

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+groups:
+  - name: ledger-observability
+    interval: 30s
+    rules:
+      - alert: LedgerWriteLatencyHighP95
+        expr: histogram_quantile(0.95, sum(rate(ledger_write_latency_seconds_bucket[5m])) by (le, tenant)) > 0.12
+        for: 10m
+        labels:
+          severity: warning
+        annotations:
+          summary: "Ledger write latency p95 high (tenant {{ $labels.tenant }})"
+          description: "ledger_write_latency_seconds p95 > 120ms for >10m. Check DB/queue."
+
+      - alert: ProjectionLagHigh
+        expr: max_over_time(ledger_projection_lag_seconds[10m]) > 30
+        for: 10m
+        labels:
+          severity: critical
+        annotations:
+          summary: "Ledger projection lag high"
+          description: "projection lag over 30s; projections falling behind ingest."
+
+      - alert: MerkleAnchorFailures
+        expr: sum(rate(ledger_merkle_anchor_failures_total[15m])) by (tenant, reason) > 0
+        for: 15m
+        labels:
+          severity: critical
+        annotations:
+          summary: "Merkle anchor failures (tenant {{ $labels.tenant }})"
+          description: "Anchoring failures detected (reason={{ $labels.reason }}). Investigate signing/storage."
+
+      - alert: AttachmentFailures
+        expr: sum(rate(ledger_attachments_encryption_failures_total[10m])) by (tenant, stage) > 0
+        for: 10m
+        labels:
+          severity: warning
+        annotations:
+          summary: "Attachment pipeline failures (tenant {{ $labels.tenant }}, stage {{ $labels.stage }})"
+          description: "Attachment encryption/sign/upload reported failures in the last 10m."