Add active/inactive/game-time timers to fleet + server pages

Fleet cards and the per-server detail hero now show three live-ticking
timers: Active (since players > 0), Inactive (since server emptied), and
Game (since InitGame in games_sp.log, back-computed from the log's own
MM:SS prefix so it stays accurate across restarts). Anchors are
persisted on `servers` and fanned out via the SSE bus; a single 1s
ticker feeds every card. Idle map cycles are filtered out so the game
timer doesn't flicker.

src/lib/ui/stores/servers.ts

@@ -1,4 +1,4 @@
-import { writable } from 'svelte/store';
+import { writable, readonly } from 'svelte/store';
 import { browser } from '$app/environment';
 
 export interface RosterPlayer {
@@ -29,10 +29,21 @@ export interface ServerStatus {
     endpoint: RconEndpoint | null;
     reason: RconFailure | null;
     replySnippet: string | null;
+    activeSince: string | null;
+    inactiveSince: string | null;
+    gameStartedAt: string | null;
+    gameEndedAt: string | null;
 }
 
 export const statusByServer = writable<Map<string, ServerStatus>>(new Map());
 
+// Shared 1s ticker for elapsed-time displays. One interval feeds every card
+// on the page instead of N per-card timers. Timer starts on the first
+// startServerStream() call in the browser.
+const _uiNow = writable(Date.now());
+export const uiNow = readonly(_uiNow);
+let tickInterval: ReturnType<typeof setInterval> | null = null;
+
 let source: EventSource | null = null;
 
 export function startServerStream(): void {
@@ -46,4 +57,7 @@ export function startServerStream(): void {
             return m;
         });
     });
+    if (tickInterval === null) {
+        tickInterval = setInterval(() => _uiNow.set(Date.now()), 1000);
+    }
 }