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/conftest.py

@@ -0,0 +1,70 @@
+from __future__ import annotations
+
+from collections.abc import Iterator
+from pathlib import Path
+
+import pytest
+import yaml
+
+from daena.config import DaenaConfig
+from daena.persistence.lmdb import LMDBBackend
+from daena.persistence.models import StoredRecord
+
+
+@pytest.fixture
+def tmp_db_path(tmp_path: Path) -> Path:
+    return tmp_path / "lmdb"
+
+
+@pytest.fixture
+def lmdb_backend(tmp_db_path: Path) -> Iterator[LMDBBackend]:
+    backend = LMDBBackend(
+        path=str(tmp_db_path),
+        map_size=10_485_760,
+    )
+    backend.open()
+    yield backend
+    backend.close()
+
+
+@pytest.fixture
+def sample_record() -> StoredRecord:
+    return StoredRecord(
+        source="test_source",
+        record_type="test",
+        body={"message": "hello"},
+        metadata={"env": "test"},
+    )
+
+
+@pytest.fixture
+def minimal_config() -> DaenaConfig:
+    return DaenaConfig()
+
+
+@pytest.fixture
+def config_file(tmp_path: Path) -> Path:
+    path = tmp_path / "daena.yaml"
+    data = {
+        "data_dir": "/tmp/daena_data",
+        "logging": {"level": "debug", "format": "json"},
+        "sources": [
+            {
+                "name": "test",
+                "type": "dummy",
+                "enabled": True,
+                "options": {"interval": 1.0},
+            }
+        ],
+        "sinks": [
+            {
+                "name": "output",
+                "type": "dummy",
+                "enabled": True,
+                "options": {},
+            }
+        ],
+    }
+    with open(path, "w") as f:
+        yaml.dump(data, f)
+    return path