fix: derive WebSocket URL from API_BASE_URL in conversation screen (#130)

* Initial plan

* fix: use API_BASE_URL for WebSocket URL in conversation screen

Co-authored-by: grillinr <169214325+grillinr@users.noreply.github.com>

* fix: merge reconnection logic from base branch while keeping API_BASE_URL approach

Co-authored-by: elifouts <116454864+elifouts@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: grillinr <169214325+grillinr@users.noreply.github.com>
Co-authored-by: elifouts <116454864+elifouts@users.noreply.github.com>
Co-authored-by: Eli Fouts <eligfouts@gmail.com>

Author: 3 people

frontend/app/conversation/[username].tsx

@@ -17,7 +17,7 @@ import { MessageBubble } from "@/components/MessageBubble";
 import { MessageComposer } from "@/components/MessageComposer";
 import { useAppColors } from "@/hooks/useAppColors";
 import { useAuth } from "@/contexts/AuthContext";
-import { getDirectMessages, createDirectMessage } from "@/services/api";
+import { API_BASE_URL, getDirectMessages, createDirectMessage } from "@/services/api";
 import { ApiDirectMessage } from "@/constants/Types";
 
 type MessageWithState = ApiDirectMessage & {
@@ -26,6 +26,19 @@ type MessageWithState = ApiDirectMessage & {
   tempId?: string;
 };
 
+const getWebSocketBaseUrl = (baseUrl?: string) => {
+  if (!baseUrl) {
+    return "";
+  }
+  if (baseUrl.startsWith("https://")) {
+    return `wss://${baseUrl.slice("https://".length)}`;
+  }
+  if (baseUrl.startsWith("http://")) {
+    return `ws://${baseUrl.slice("http://".length)}`;
+  }
+  return baseUrl;
+};
+
 export default function ConversationScreen() {
   const colors = useAppColors();
   const insets = useSafeAreaInsets();
@@ -74,14 +87,11 @@ export default function ConversationScreen() {
     let reconnectAttempts = 0;
     let reconnectTimeoutId: ReturnType<typeof setTimeout> | null = null;
     let isActive = true;
-
-    // Connect to WebSocket (reuse existing connection pattern from terminal)
-    const protocol = __DEV__ ? "ws" : "wss";
-    const host = __DEV__ ? "10.0.2.2:8080" : "devbits.ddns.net";
-    const wsUrl = `${protocol}://${host}/messages/${encodeURIComponent(
+    // Connect to WebSocket using API_BASE_URL
+    const wsBase = getWebSocketBaseUrl(API_BASE_URL);
+    const wsUrl = `${wsBase}/messages/${encodeURIComponent(
       user.username
     )}/stream?token=${encodeURIComponent(token)}`;
-
     const connect = () => {
       if (!isActive) {
         return;