more work on attachments

* fix frontend env usage

apps/client/src/lib/config.ts

@@ -0,0 +1,36 @@
+declare global {
+  interface Window {
+    CONFIG?: Record<string, string>;
+  }
+}
+
+export function getAppUrl(): string {
+  let appUrl = window.CONFIG?.APP_URL || process.env.APP_URL;
+
+  if (!appUrl) {
+    appUrl = import.meta.env.DEV
+      ? "http://localhost:3000"
+      : window.location.protocol + "//" + window.location.host;
+  }
+
+  return appUrl;
+}
+
+export function getBackendUrl(): string {
+  return getAppUrl() + "/api";
+}
+
+export function getCollaborationUrl(): string {
+  const COLLAB_PATH = "/collab";
+
+  const wsProtocol = getAppUrl().startsWith("https") ? "wss" : "ws";
+  return `${wsProtocol}://${getAppUrl().split("://")[1]}${COLLAB_PATH}`;
+}
+
+export function getAvatarUrl(avatarUrl: string) {
+  if (avatarUrl.startsWith("http")) {
+    return avatarUrl;
+  }
+
+  return getBackendUrl() + "/attachments/img/avatar/" + avatarUrl;
+}