Refactor alias handling in incident and live pages

- Updated the `load` and `connectStream` functions to accept an optional `aliasOverride` parameter, allowing for more flexible alias filtering.
- Enhanced the logic for determining the active alias based on URL parameters, ensuring accurate data retrieval and stream connections.
- Improved consistency in alias management across both incident and live pages, streamlining user experience.

web/src/routes/incidents/+page.svelte

@@ -114,12 +114,13 @@
 		}
 	}
 
-	async function load() {
+	async function load(aliasOverride?: string) {
 		loading = true;
 		err = null;
 		try {
+			const activeAlias = aliasOverride ?? aliasFilter;
 			const env = await fetchAggIncidents({
-				aliases: aliasFilter === 'all' ? undefined : aliasFilter
+				aliases: activeAlias === 'all' ? undefined : activeAlias
 			});
 			data = env.data ?? null;
 			partial = !!env.partial;
@@ -151,11 +152,12 @@
 	$effect(() => {
 		queryKey;
 		if (typeof window === 'undefined') return;
-		aliasFilter = parseAliasFilter(page.url.searchParams.get('aliases'));
+		const nextAlias = parseAliasFilter(page.url.searchParams.get('aliases'));
+		aliasFilter = nextAlias;
 		refreshSeconds = parseRefresh(page.url.searchParams.get('refresh'));
 		refreshInput = String(refreshSeconds);
 		restartPolling();
-		void load();
+		void load(nextAlias);
 	});
 
 	let staleSeconds = $derived.by(() =>

web/src/routes/live/+page.svelte

@@ -151,11 +151,12 @@
 		}, 250);
 	}
 
-	function connectStream() {
+	function connectStream(aliasOverride?: string) {
 		closeStream();
 		clearReconnectTimer();
 		err = null;
-		const aliasesParam = aliasFilter === 'all' ? undefined : aliasFilter;
+		const activeAlias = aliasOverride ?? aliasFilter;
+		const aliasesParam = activeAlias === 'all' ? undefined : activeAlias;
 		const url = liveEventsUrl({ aliases: aliasesParam });
 		const next = new EventSource(url);
 		next.onopen = () => {
@@ -214,8 +215,9 @@
 	$effect(() => {
 		queryKey;
 		if (typeof window === 'undefined') return;
-		aliasFilter = parseAliasFilter(page.url.searchParams.get('aliases'));
+		const nextAlias = parseAliasFilter(page.url.searchParams.get('aliases'));
-		connectStream();
+		aliasFilter = nextAlias;
+		connectStream(nextAlias);
 	});
 
 	let staleSeconds = $derived.by(() =>