Phase 4: Implement REST API component

- Add FastAPI application with lifespan management
- Implement bearer token authentication (read/admin levels)
- Create comprehensive REST API routes:
  - Nodes: list, get by public key
  - Node tags: CRUD operations
  - Messages: list with filters, get by ID
  - Advertisements: list with filters, get by ID
  - Telemetry: list with filters, get by ID
  - Trace paths: list with filters, get by ID
  - Commands: send message, channel message, advertisement
  - Dashboard: stats API and HTML dashboard
- Add API CLI command for running the server
- Create API test suite with 44 passing tests

Routes use proper RESTful status codes (201 Created, 204 No Content).
Authentication is optional - when keys not configured, endpoints are open.

tests/test_api/test_telemetry.py

@@ -0,0 +1,58 @@
+"""Tests for telemetry API routes."""
+
+import pytest
+
+
+class TestListTelemetry:
+    """Tests for GET /telemetry endpoint."""
+
+    def test_list_telemetry_empty(self, client_no_auth):
+        """Test listing telemetry when database is empty."""
+        response = client_no_auth.get("/api/v1/telemetry")
+        assert response.status_code == 200
+        data = response.json()
+        assert data["items"] == []
+        assert data["total"] == 0
+
+    def test_list_telemetry_with_data(self, client_no_auth, sample_telemetry):
+        """Test listing telemetry with data in database."""
+        response = client_no_auth.get("/api/v1/telemetry")
+        assert response.status_code == 200
+        data = response.json()
+        assert len(data["items"]) == 1
+        assert data["total"] == 1
+        assert data["items"][0]["node_public_key"] == sample_telemetry.node_public_key
+        assert data["items"][0]["parsed_data"] == sample_telemetry.parsed_data
+
+    def test_list_telemetry_filter_by_node(self, client_no_auth, sample_telemetry):
+        """Test filtering telemetry by node public key."""
+        response = client_no_auth.get(
+            f"/api/v1/telemetry?node_public_key={sample_telemetry.node_public_key}"
+        )
+        assert response.status_code == 200
+        data = response.json()
+        assert len(data["items"]) == 1
+
+        response = client_no_auth.get(
+            "/api/v1/telemetry?node_public_key=nonexistent"
+        )
+        assert response.status_code == 200
+        data = response.json()
+        assert len(data["items"]) == 0
+
+
+class TestGetTelemetry:
+    """Tests for GET /telemetry/{id} endpoint."""
+
+    def test_get_telemetry_success(self, client_no_auth, sample_telemetry):
+        """Test getting a specific telemetry record."""
+        response = client_no_auth.get(f"/api/v1/telemetry/{sample_telemetry.id}")
+        assert response.status_code == 200
+        data = response.json()
+        assert data["id"] == sample_telemetry.id
+        assert data["node_public_key"] == sample_telemetry.node_public_key
+
+    def test_get_telemetry_not_found(self, client_no_auth):
+        """Test getting a non-existent telemetry record."""
+        response = client_no_auth.get("/api/v1/telemetry/nonexistent-id")
+        assert response.status_code == 404