Add unique and new player metrics (Refs #142)

tests/unit/ui-metrics.test.ts

@@ -6,10 +6,17 @@ import {
     metricLobbyAxis,
     metricNumber,
     metricPercent,
-    metricPeriodLabels
+    metricPeriodLabels,
+    metricPlayerPaths
 } from '../../src/lib/ui/metrics.js';
 
 describe('metric presentation', () => {
+    it('breaks player lines at missing history while retaining real zeroes and isolated points', () => {
+        const paths = metricPlayerPaths([null, 2, 0, null, 1], 2);
+        expect(paths.line).toBe('M30,0 L50,100 M90,50');
+        expect(paths.area).toBe('M30,0 L50,100 L50,100 L30,100 Z M90,50 L90,100 L90,100 Z');
+        expect(metricPlayerPaths([null, null], 1)).toEqual({ line: '', area: '' });
+    });
     it('normalizes partial buckets by captured wall time and preserves unknown lobby counts', () => {
         expect(metricAverageLobbies(14 * 24, 24)).toBe(14);
         expect(metricAverageLobbies(14 * 0.5, 0.5)).toBe(14);