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

tests/test_layout.py

@@ -0,0 +1,83 @@
+from __future__ import annotations
+
+from daena.config import (
+    DaenaConfig,
+    MetricsConfig,
+    ProcessorConfig,
+    SinkConfig,
+    SourceConfig,
+)
+from daena.core.layout import preview_message, render_layout
+
+
+def _config() -> DaenaConfig:
+    config = DaenaConfig()
+    config.persistence.lmdb.path = "/tmp/daena/data"
+    config.sources = [
+        SourceConfig(name="dummy", type="dummy", options={"interval": 2.0}),
+        SourceConfig(
+            name="system",
+            type="journald",
+            enabled=False,
+            options={"units": ["ssh.service"]},
+        ),
+    ]
+    config.processors = [
+        ProcessorConfig(name="host", type="enricher", options={"static": {"env": "local"}}),
+        ProcessorConfig(name="keep", type="filter", options={"drop": {"body.priority": "7"}}),
+    ]
+    config.sinks = [
+        SinkConfig(name="log", type="dummy"),
+        SinkConfig(
+            name="loki",
+            type="loki",
+            options={"url": "http://127.0.0.1:3100/loki/api/v1/push"},
+        ),
+    ]
+    config.logging.verbose = True
+    return config
+
+
+def test_layout_is_a_single_pipeline_line() -> None:
+    text = render_layout(_config(), "./daena.yaml")
+    assert "┌" not in text
+    assert "▼" not in text
+    flow = text.splitlines()[1]
+    assert flow.index("dummy") < flow.index("host")
+    assert flow.index("host") < flow.index("lmdb")
+    assert flow.index("lmdb") < flow.index("log")
+    assert "daena 0.1.0  ./daena.yaml" in text
+    assert "/tmp/daena/data" in text
+    assert "127.0.0.1:8642   127.0.0.1:8643" in text
+
+
+def test_layout_names_each_plugin_once() -> None:
+    text = render_layout(_config(), None)
+    flow = text.splitlines()[1]
+    assert flow == " → ".join(
+        [
+            "dummy (2s), system (journald, off)",
+            "host (enricher), keep (filter)",
+            "lmdb",
+            "log (dummy), loki (127.0.0.1:3100)",
+        ]
+    )
+    assert "daena 0.1.0  defaults" in text
+
+
+def test_layout_skips_empty_stages_and_disabled_metrics() -> None:
+    config = DaenaConfig()
+    config.api.metrics = MetricsConfig(enabled=False)
+    text = render_layout(config, None)
+    assert "→ lmdb" not in text
+    assert text.splitlines()[1] == "lmdb"
+    assert text.splitlines()[-1] == "127.0.0.1:8642"
+
+
+def test_preview_message_uses_message_then_clips() -> None:
+    assert preview_message({"message": "daena heartbeat #1"}) == "daena heartbeat #1"
+    assert preview_message({"message": "a\nb"}) == "a b"
+    assert preview_message({"counter": 1}) == '{"counter":1}'
+    clipped = preview_message({"message": "x" * 130}, limit=10)
+    assert clipped.endswith("…")
+    assert len(clipped) == 10