feat: per-sink delivery, journal forwarding, and operational API

Persistence:
- one delivery state per sink, with claim, crash recovery, and index replacement
- retention for delivered and dead records
- LMDB writes moved off the event loop

Pipeline:
- one attempt per dispatch, with the next try scheduled by next_retry_at
- backpressure through max_queue_size
- reload re-reads YAML; SIGTERM drains and SIGHUP reloads

Plugins:
- journald source, enricher and filter processors, Loki sink
- built-ins register when entry points are missing

API and CLI:
- health, metrics, per-sink queue, and dead-letter replay
- startup prints the pipeline on one line

Tests:
- dispatch, plugins, metrics, CLI, and persistence coverage

config/daena.yaml

@@ -8,18 +8,59 @@ pid_file: /run/daena/daena.pid
 logging:
   level: info
   format: json
+  verbose: false
 
 api:
   grpc:
     host: 127.0.0.1
     port: 8642
     max_workers: 10
+  metrics:
+    enabled: true
+    host: 127.0.0.1
+    port: 8643
 
 pipeline:
   batch_size: 100
   flush_interval: 5.0
   max_queue_size: 10000
 
+retention:
+  delivered_ttl_seconds: 86400
+  dead_ttl_seconds: 604800
+  interval_seconds: 60
+
+health:
+  max_pending_age_seconds: 300
+
+# journald source, enricher, filter, and loki sink are registered plugins.
+# Example:
+# sources:
+#   - name: system
+#     type: journald
+#     options:
+#       units: ["ssh.service"]
+#       cursor_path: /var/lib/daena/journal.cursor
+# processors:
+#   - name: host
+#     type: enricher
+#     options:
+#       hostname: true
+#       static:
+#         env: prod
+#   - name: drop_debug
+#     type: filter
+#     options:
+#       drop:
+#         body.priority: "7"
+# sinks:
+#   - name: loki
+#     type: loki
+#     options:
+#       url: http://127.0.0.1:3100/loki/api/v1/push
+#       labels:
+#         job: daena
+
 persistence:
   backend: lmdb
   lmdb: