Replace instance metrics with map lobby counts (Refs #139)

tests/unit/metrics.test.ts

@@ -77,6 +77,7 @@ describe('historical metrics', () => {
             });
             expect(result.maps).toHaveLength(1);
             expect(result.maps[0].matches).toEqual(result.matches);
+            expect(result.maps[0].running).toEqual({ average: null, peak: 0, capturedHours: 0 });
             expect(result.registeredServerCount).toBe(0);
             expect(result.servers).toEqual([]);
             expect(result.scopeOptions.maps).not.toContainEqual({ game: 't5', map: 'Future Map' });
@@ -365,6 +366,8 @@ describe('historical metrics', () => {
         expect(later.maps[0].availabilityUnknown * 3600).toBeCloseTo(90);
         expect(later.pooledAvailability.value).toBeNull();
         expect(initial.running).toEqual({ average: null, peak: 0, capturedHours: 0 });
+        expect(initial.maps[0].running).toEqual(initial.running);
+        expect(later.maps[0].running).toEqual({ average: 1, peak: 1, capturedHours: 90 / 3600 });
     });
 
     it('returns clipped interval boundaries and marks only partial UTC buckets', async () => {
@@ -597,6 +600,7 @@ describe('historical metrics', () => {
         expect(result.running.average).toBeCloseTo(1.6);
         expect(result.running.peak).toBe(3);
         expect(result.running.capturedHours * 3600).toBeCloseTo(150);
+        expect(result.maps[0].running).toEqual(result.running);
         expect(result.previous.running.average).toBe(4);
         expect(result.previous.running.peak).toBe(4);
         expect(result.previous.running.capturedHours * 3600).toBeCloseTo(90);
@@ -610,6 +614,50 @@ describe('historical metrics', () => {
         );
     });
 
+    it('counts concurrent lobbies per recorded game/map across reused names, clipped intervals and collection gaps', async () => {
+        const { recordMetrics, readMetrics } =
+            await import('../../src/lib/server/fleet/metrics.js');
+        const now = Date.UTC(2026, 0, 3, 12);
+        const since = now - 86400_000;
+        const one = { server: 'one', game: 't5', map: 'Moon', players: 0, capacity: null };
+        const two = { ...one, server: 'two', players: null };
+        const otherGame = { ...one, server: 't6-one', game: 't6' };
+        recordMetrics([one, two, otherGame], since - 30_000);
+        recordMetrics([{ ...one, server: 'three', players: 2 }], since + 15_000);
+        recordMetrics(
+            [
+                otherGame,
+                { ...otherGame, server: 't6-two' },
+                { ...otherGame, server: 't6-three' },
+                { ...one, map: 'Kino Der Toten' }
+            ],
+            since + 45_000
+        );
+        // Both lobby names are reused after the map was absent from a collection.
+        recordMetrics([one, { ...two, players: 0 }], now - 30_000);
+        // A snapshot with no elapsed time must not inflate the captured peak.
+        recordMetrics([one, two, { ...one, server: 'three' }], now);
+        const result = readMetrics(1, now);
+        const moon = result.maps.find((map) => map.game === 't5' && map.map === 'Moon')!;
+        expect(moon.running.average).toBeCloseTo(1.6);
+        expect(moon.running.peak).toBe(2);
+        expect(moon.running.capturedHours * 3600).toBeCloseTo(75);
+        expect(moon.idle * 3600).toBeCloseTo(75);
+        expect(moon.unknown * 3600).toBeCloseTo(15);
+        expect(moon.observed + moon.unknown).toBeCloseTo(
+            moon.running.average! * moon.running.capturedHours
+        );
+        const t6 = result.maps.find((map) => map.game === 't6')!;
+        expect(t6.running.average).toBeCloseTo(285 / 105);
+        expect(t6.running.peak).toBe(3);
+        expect(t6.running.capturedHours * 3600).toBeCloseTo(105);
+        const kino = result.maps.find((map) => map.map === 'Kino Der Toten')!;
+        expect(kino.running).toEqual({ average: 1, peak: 1, capturedHours: 90 / 3600 });
+        const scoped = readMetrics({ days: 1, game: 't5', map: 'Moon', timeZone: 'UTC' }, now);
+        expect(scoped.maps).toEqual([moon]);
+        expect(scoped.running).toEqual(moon.running);
+    });
+
     it('matches current policy context through map aliases and prefers the durable owner', async () => {
         const { recordMetrics, readMetrics } =
             await import('../../src/lib/server/fleet/metrics.js');