feat: Phase 3 & 4 — monitoring, discovery, polish, deployment

Phase 3 — Discovery & Monitoring:
- Network scanner: nmap wrapper + mock fallback, fingerprint service (35 signatures)
- Status checker: ping/http/https/tcp/ssh/prometheus/health per-node checks
- APScheduler: status checks every 60s, WebSocket broadcast
- WebSocket /ws/status: live node status updates to frontend
- Sidebar panels: Pending Devices, Hidden Devices, Scan History
- Auth token persisted to localStorage (survive page refresh)
- 24 new backend tests (scan flow + status_checker)

Phase 4 — Polish & Deployment:
- Auto-layout: Dagre hierarchical TB via Toolbar button
- Export PNG: html-to-image download via Toolbar button
- Scan config modal: CIDR ranges + check interval, GET/POST /api/v1/scan/config
- Dockerfile.backend (Python 3.13 slim + nmap), Dockerfile.frontend (nginx)
- docker-compose.yml with data volume and NET_RAW cap for ping
- scripts/lxc-install.sh: Proxmox VE systemd bootstrap
- README.md: quick-start, config reference, stack overview

backend/tests/test_scan.py

@@ -0,0 +1,161 @@
+"""Tests for scan routes: trigger, pending devices, approve/hide/ignore."""
+from unittest.mock import AsyncMock, patch
+
+import pytest
+from httpx import AsyncClient
+
+from app.db.models import PendingDevice
+
+
+@pytest.fixture
+async def headers(client: AsyncClient):
+    res = await client.post("/api/v1/auth/login", json={"username": "admin", "password": "admin"})
+    token = res.json()["access_token"]
+    return {"Authorization": f"Bearer {token}"}
+
+
+@pytest.fixture
+async def pending_device(db_session):
+    import uuid
+    device = PendingDevice(
+        id=str(uuid.uuid4()),
+        ip="192.168.1.100",
+        mac="aa:bb:cc:dd:ee:ff",
+        hostname="my-server",
+        os="Linux",
+        services=[{"port": 22, "name": "ssh"}],
+        suggested_type="server",
+        status="pending",
+    )
+    db_session.add(device)
+    await db_session.commit()
+    await db_session.refresh(device)
+    return device
+
+
+# --- Trigger scan ---
+
+@pytest.mark.asyncio
+async def test_trigger_scan_requires_auth(client: AsyncClient):
+    res = await client.post("/api/v1/scan/trigger")
+    # FastAPI's OAuth2PasswordBearer returns 403 when no token is provided
+    assert res.status_code in (401, 403)
+
+
+@pytest.mark.asyncio
+async def test_trigger_scan_creates_run(client: AsyncClient, headers):
+    with (
+        patch("app.api.routes.scan._background_scan", new_callable=AsyncMock),
+        patch("app.api.routes.scan._load_ranges", return_value=["192.168.1.0/24"]),
+    ):
+        res = await client.post("/api/v1/scan/trigger", headers=headers)
+    assert res.status_code == 200
+    data = res.json()
+    assert data["status"] == "running"
+    assert data["ranges"] == ["192.168.1.0/24"]
+    assert "id" in data
+
+
+# --- Pending devices ---
+
+@pytest.mark.asyncio
+async def test_list_pending_empty(client: AsyncClient, headers):
+    res = await client.get("/api/v1/scan/pending", headers=headers)
+    assert res.status_code == 200
+    assert res.json() == []
+
+
+@pytest.mark.asyncio
+async def test_list_pending_returns_device(client: AsyncClient, headers, pending_device):
+    res = await client.get("/api/v1/scan/pending", headers=headers)
+    assert res.status_code == 200
+    data = res.json()
+    assert len(data) == 1
+    assert data[0]["ip"] == "192.168.1.100"
+    assert data[0]["hostname"] == "my-server"
+
+
+# --- Approve device ---
+
+@pytest.mark.asyncio
+async def test_approve_device(client: AsyncClient, headers, pending_device):
+    node_payload = {
+        "label": "My Server",
+        "type": "server",
+        "ip": "192.168.1.100",
+        "hostname": "my-server",
+        "status": "unknown",
+        "services": [],
+    }
+    res = await client.post(
+        f"/api/v1/scan/pending/{pending_device.id}/approve",
+        json=node_payload,
+        headers=headers,
+    )
+    assert res.status_code == 200
+    data = res.json()
+    assert data["approved"] is True
+    assert "node_id" in data
+
+    # Device should no longer appear in pending list
+    pending_res = await client.get("/api/v1/scan/pending", headers=headers)
+    assert pending_res.json() == []
+
+
+@pytest.mark.asyncio
+async def test_approve_nonexistent_device(client: AsyncClient, headers):
+    node_payload = {
+        "label": "Ghost",
+        "type": "generic",
+        "ip": "10.0.0.1",
+        "status": "unknown",
+        "services": [],
+    }
+    res = await client.post(
+        "/api/v1/scan/pending/nonexistent-id/approve",
+        json=node_payload,
+        headers=headers,
+    )
+    assert res.status_code == 200
+    assert res.json()["approved"] is False
+
+
+# --- Hide device ---
+
+@pytest.mark.asyncio
+async def test_hide_device(client: AsyncClient, headers, pending_device):
+    res = await client.post(f"/api/v1/scan/pending/{pending_device.id}/hide", headers=headers)
+    assert res.status_code == 200
+    assert res.json()["hidden"] is True
+
+    # Should no longer appear in pending
+    pending_res = await client.get("/api/v1/scan/pending", headers=headers)
+    assert pending_res.json() == []
+
+    # Should appear in hidden
+    hidden_res = await client.get("/api/v1/scan/hidden", headers=headers)
+    assert len(hidden_res.json()) == 1
+
+
+# --- Ignore device ---
+
+@pytest.mark.asyncio
+async def test_ignore_device(client: AsyncClient, headers, pending_device):
+    res = await client.post(f"/api/v1/scan/pending/{pending_device.id}/ignore", headers=headers)
+    assert res.status_code == 200
+    assert res.json()["ignored"] is True
+
+    # Device should be gone from both pending and hidden
+    pending_res = await client.get("/api/v1/scan/pending", headers=headers)
+    assert pending_res.json() == []
+    hidden_res = await client.get("/api/v1/scan/hidden", headers=headers)
+    assert hidden_res.json() == []
+
+
+# --- Scan runs ---
+
+@pytest.mark.asyncio
+async def test_list_runs_empty(client: AsyncClient, headers):
+    res = await client.get("/api/v1/scan/runs", headers=headers)
+    assert res.status_code == 200
+    assert res.json() == []