feat: add configurable API server URLs and CORS settings for development

Adds environment variables to configure API server URLs and CORS settings
for development environments, enabling flexible multi-server setups and
cross-origin testing.

web/src/lib/utils/server.ts

@@ -1,15 +1,48 @@
 import { retrieveServerConfig } from '$lib/stores/server-config.store';
-import { initLanguage } from '$lib/utils';
+import { AbortError, initLanguage, sleep } from '$lib/utils';
 import { defaults } from '@immich/sdk';
 import { memoize } from 'lodash-es';
 
 type Fetch = typeof fetch;
 
+const api_server: string = '@IMMICH_API_SERVER@';
+
+const tryServers = async (fetchFn: typeof fetch) => {
+  const servers = api_server
+    .split(',')
+    .map((v) => v.trim())
+    .filter((v) => v !== '');
+  if (servers.length === 0) {
+    return true;
+  }
+  // servers are in priority order, try in parallel, use first success
+  const fetchers = servers.map(async (url: string) => {
+    const response = await fetchFn(url + '/server/config');
+    if (response.ok) {
+      return url;
+    }
+    throw new AbortError();
+  });
+  try {
+    const urlWinner = await Promise.any(fetchers);
+    defaults.baseUrl = urlWinner;
+    defaults.fetch = (url, options) => fetchFn(url, { credentials: 'include', ...options });
+  } catch (e) {
+    console.error(e);
+    return false;
+  }
+};
+
 async function _init(fetch: Fetch) {
   // set event.fetch on the fetch-client used by @immich/sdk
   // https://kit.svelte.dev/docs/load#making-fetch-requests
   // https://github.com/oazapfts/oazapfts/blob/main/README.md#fetch-options
   defaults.fetch = fetch;
+  try {
+    await Promise.race([tryServers(fetch), sleep(5000)]);
+  } catch {
+    throw 'Could not connect to any server';
+  }
   await initLanguage();
   await retrieveServerConfig();
 }