feat: v0.1.4 — device intelligence dashboard

Add tabbed dashboard at /dashboard/ with three D3.js visualizations:
- Vendor treemap (devices grouped by type and vendor)
- SSID social graph (force-directed, shared probed SSIDs as edges)
- Fingerprint clusters (packed circles by device behavior)

Intelligence API endpoints at /api/v1/intelligence/ with param
validation. Dashboard built on htmx + Pico CSS dark theme + D3 v7,
all vendored locally (make vendor). 13 new tests (59 total).

tests/test_dashboard/test_views.py

@@ -0,0 +1,29 @@
+"""Dashboard view tests."""
+
+
+def test_dashboard_index(client):
+    """Test main dashboard page loads."""
+    response = client.get('/dashboard/')
+    assert response.status_code == 200
+    assert b'Device Intelligence' in response.data
+
+
+def test_dashboard_tab_vendor_treemap(client):
+    """Test vendor treemap partial loads."""
+    response = client.get('/dashboard/tab/vendor-treemap')
+    assert response.status_code == 200
+    assert b'vendor-treemap' in response.data
+
+
+def test_dashboard_tab_ssid_graph(client):
+    """Test SSID graph partial loads."""
+    response = client.get('/dashboard/tab/ssid-graph')
+    assert response.status_code == 200
+    assert b'ssid-graph' in response.data
+
+
+def test_dashboard_tab_fingerprint_clusters(client):
+    """Test fingerprint clusters partial loads."""
+    response = client.get('/dashboard/tab/fingerprint-clusters')
+    assert response.status_code == 200
+    assert b'fingerprint-clusters' in response.data