feat(ops): add database backup strategy and log aggregation stack

- Add pg-backup container with daily automated pg_dump (02:00 UTC) and 7-day retention
- Add backup/restore scripts with documented recovery procedure
- Add Loki + Promtail for centralized log aggregation from all Docker containers
- Add Loki as Grafana datasource with correlation ID derived fields
- Add Grafana logs dashboard with volume, error rate, HTTP request, and log viewer panels
- Configure Promtail to parse Pino structured JSON logs with level/context labels
- Enhance LoggerService with string-level formatter and service base field
- Configure 15-day log retention in Loki

Co-Authored-By: Paperclip <noreply@paperclip.ing>

monitoring/loki/loki-config.yml

@@ -0,0 +1,58 @@
+auth_enabled: false
+
+server:
+  http_listen_port: 3100
+  grpc_listen_port: 9096
+
+common:
+  path_prefix: /loki
+  storage:
+    filesystem:
+      chunks_directory: /loki/chunks
+      rules_directory: /loki/rules
+  replication_factor: 1
+  ring:
+    instance_addr: 127.0.0.1
+    kvstore:
+      store: inmemory
+
+schema_config:
+  configs:
+    - from: 2024-01-01
+      store: tsdb
+      object_store: filesystem
+      schema: v13
+      index:
+        prefix: index_
+        period: 24h
+
+limits_config:
+  reject_old_samples: true
+  reject_old_samples_max_age: 168h   # 7 days
+  max_entries_limit_per_query: 5000
+  ingestion_rate_mb: 4
+  ingestion_burst_size_mb: 6
+
+storage_config:
+  tsdb_shipper:
+    active_index_directory: /loki/tsdb-index
+    cache_location: /loki/tsdb-cache
+
+compactor:
+  working_directory: /loki/compactor
+  compaction_interval: 10m
+  retention_enabled: true
+  retention_delete_delay: 2h
+  retention_delete_worker_count: 150
+  delete_request_store: filesystem
+
+# Retention: keep logs for 15 days
+chunk_store_config:
+  chunk_cache_config:
+    embedded_cache:
+      enabled: true
+      max_size_mb: 100
+
+table_manager:
+  retention_deletes_enabled: true
+  retention_period: 360h   # 15 days