feat: implement daena MVP core service

Complete implementation of the daena log/event collection service:

Core runtime:
- DaenaRuntime service lifecycle (start/stop/reload)
- Pipeline orchestrator with source/persist/dispatch flow
- LMDB persistence backend with key-prefix partitioning
- Plugin discovery via Python entry points

Pipeline:
- Source/Processor/Sink ABC interfaces with DeliveryResult
- DummySource for testing and development
- DummySink and HTTPSink implementations
- PassthroughProcessor
- Record dataclass for in-memory records
- StoredRecord model with RecordState tracking

REST API (FastAPI, v1):
- GET /system/{status,health,config}
- GET /plugins
- GET /queue, /queue/{pending,dead}
- GET /sinks
- Versioned under /api/v1 prefix

CLI (Typer):
- status, health, queue, sinks, plugins, config, version

Persistence (LMDB):
- Single-database key-prefix design (no named DBs)
- Index keys: idx:{state}:{ts}\x00{id}
- Record keys: rec:{id}
- Full CRUD: put/get/ack/nack/dead/update_state
- Pending/retry/dead-letter queries with state filtering
- delete_old for TTL-based retention

Deployment:
- systemd unit file (deploy/daena.service)
- Example YAML config (config/daena.yaml)
- Entry points: daena (CLI), daena-serve (uvicorn server)

Quality:
- 23 unit tests covering config, persistence, pipeline
- ruff linting and formatting pass clean
- Py3.13 compatible, uv-managed, pyenv-pinned
- GPG-signed commit on dev branch

tests/test_persistence.py

@@ -0,0 +1,107 @@
+from __future__ import annotations
+
+from daena.persistence.lmdb import LMDBBackend
+from daena.persistence.models import RecordState, StoredRecord
+
+
+def test_put_and_get(lmdb_backend: LMDBBackend, sample_record: StoredRecord) -> None:
+    lmdb_backend.put(sample_record)
+    retrieved = lmdb_backend.get(sample_record.record_id)
+    assert retrieved is not None
+    assert retrieved.record_id == sample_record.record_id
+    assert retrieved.source == "test_source"
+    assert retrieved.body == {"message": "hello"}
+
+
+def test_pending_returns_new_records(
+    lmdb_backend: LMDBBackend, sample_record: StoredRecord
+) -> None:
+    lmdb_backend.put(sample_record)
+    pending = lmdb_backend.pending(limit=10)
+    assert len(pending) == 1
+    assert pending[0].record_id == sample_record.record_id
+
+
+def test_ack(lmdb_backend: LMDBBackend, sample_record: StoredRecord) -> None:
+    lmdb_backend.put(sample_record)
+    lmdb_backend.ack(sample_record.record_id)
+    retrieved = lmdb_backend.get(sample_record.record_id)
+    assert retrieved is not None
+    assert retrieved.state == RecordState.delivered
+    pending = lmdb_backend.pending()
+    assert all(r.record_id != sample_record.record_id for r in pending)
+
+
+def test_nack(lmdb_backend: LMDBBackend, sample_record: StoredRecord) -> None:
+    lmdb_backend.put(sample_record)
+    lmdb_backend.nack(sample_record.record_id, error="test error", retry_delay=1.0)
+    retrieved = lmdb_backend.get(sample_record.record_id)
+    assert retrieved is not None
+    assert retrieved.state == RecordState.failed
+    assert retrieved.last_error == "test error"
+    assert retrieved.next_retry_at is not None
+
+
+def test_dead(lmdb_backend: LMDBBackend, sample_record: StoredRecord) -> None:
+    lmdb_backend.put(sample_record)
+    lmdb_backend.dead(sample_record.record_id, error="permanent failure")
+    retrieved = lmdb_backend.get(sample_record.record_id)
+    assert retrieved is not None
+    assert retrieved.state == RecordState.dead
+
+
+def test_count(lmdb_backend: LMDBBackend, sample_record: StoredRecord) -> None:
+    assert lmdb_backend.count() == 0
+    lmdb_backend.put(sample_record)
+    assert lmdb_backend.count() == 1
+    assert lmdb_backend.count(RecordState.pending) == 1
+
+
+def test_list_by_state(lmdb_backend: LMDBBackend, sample_record: StoredRecord) -> None:
+    lmdb_backend.put(sample_record)
+    pending = lmdb_backend.list_by_state(RecordState.pending)
+    assert len(pending) == 1
+    lmdb_backend.ack(sample_record.record_id)
+    delivered = lmdb_backend.list_by_state(RecordState.delivered)
+    assert len(delivered) == 1
+
+
+def test_delete_old(lmdb_backend: LMDBBackend, sample_record: StoredRecord) -> None:
+    lmdb_backend.put(sample_record)
+    lmdb_backend.ack(sample_record.record_id)
+    before = "2100-01-01T00:00:00"
+    removed = lmdb_backend.delete_old(before, state=RecordState.delivered)
+    assert removed == 1
+    assert lmdb_backend.get(sample_record.record_id) is None
+
+
+def test_iter_pending(lmdb_backend: LMDBBackend, sample_record: StoredRecord) -> None:
+    lmdb_backend.put(sample_record)
+    records = list(lmdb_backend.iter_pending())
+    assert len(records) == 1
+    assert records[0].record_id == sample_record.record_id
+
+
+def test_update_state(lmdb_backend: LMDBBackend, sample_record: StoredRecord) -> None:
+    lmdb_backend.put(sample_record)
+    lmdb_backend.update_state(sample_record.record_id, RecordState.failed, last_error="oops")
+    retrieved = lmdb_backend.get(sample_record.record_id)
+    assert retrieved is not None
+    assert retrieved.state == RecordState.failed
+    assert retrieved.last_error == "oops"
+
+
+def test_stored_record_to_from_dict(sample_record: StoredRecord) -> None:
+    d = sample_record.to_dict()
+    restored = StoredRecord.from_dict(d)
+    assert restored.record_id == sample_record.record_id
+    assert restored.source == sample_record.source
+    assert restored.body == sample_record.body
+    assert restored.state == sample_record.state
+
+
+def test_ready_for_retry(lmdb_backend: LMDBBackend, sample_record: StoredRecord) -> None:
+    lmdb_backend.put(sample_record)
+    lmdb_backend.nack(sample_record.record_id, "retry later", retry_delay=0)
+    ready = lmdb_backend.ready_for_retry(limit=10)
+    assert len(ready) == 1