fix(web): address bugbot review issues from second pass

- Replace Node.js Buffer.byteLength() with TextEncoder in MuxProvider
  (browser-safe UTF-8 byte counting for the ring buffer)
- Remove write-only sessionSubscribedRef from MuxProvider
- Remove dead DirectTerminalLocation, DirectTerminalWsUrlOptions,
  buildDirectTerminalWsUrl and their tests (superseded by mux)
- Call closeTerminal(sessionId) on DirectTerminal unmount so PTY
  processes are released and openedTerminalsRef stays accurate
- Add cleanup return to mux effect in useSessionEvents so pending
  refresh timers and abort controllers are cleared on unmount

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/web/src/components/DirectTerminal.tsx

@@ -25,20 +25,6 @@ interface DirectTerminalProps {
   reloadCommand?: string;
 }
 
-interface DirectTerminalLocation {
-  protocol: string;
-  hostname: string;
-  host: string;
-  port: string;
-}
-
-interface DirectTerminalWsUrlOptions {
-  location: DirectTerminalLocation;
-  sessionId: string;
-  proxyWsPath?: string;
-  directTerminalPort?: string;
-}
-
 type TerminalVariant = "agent" | "orchestrator";
 
 
@@ -106,26 +92,6 @@ export function buildTerminalThemes(variant: TerminalVariant): { dark: ITheme; l
   return { dark, light };
 }
 
-export function buildDirectTerminalWsUrl({
-  location,
-  sessionId,
-  proxyWsPath,
-  directTerminalPort,
-}: DirectTerminalWsUrlOptions): string {
-  const protocol = location.protocol === "https:" ? "wss:" : "ws:";
-  if (proxyWsPath) {
-    // Path-based proxy uses host so non-standard ports are preserved.
-    return `${protocol}//${location.host}${proxyWsPath}?session=${encodeURIComponent(sessionId)}`;
-  }
-
-  if (location.port === "" || location.port === "443" || location.port === "80") {
-    return `${protocol}//${location.hostname}/ao-terminal-ws?session=${encodeURIComponent(sessionId)}`;
-  }
-
-  const port = directTerminalPort ?? "14801";
-  return `${protocol}//${location.hostname}:${port}/ws?session=${encodeURIComponent(sessionId)}`;
-}
-
 /**
  * Direct xterm.js terminal with native WebSocket connection.
  * Implements Extended Device Attributes (XDA) handler to enable
@@ -149,7 +115,7 @@ export function DirectTerminal({
   const searchParams = useSearchParams();
   const { resolvedTheme } = useTheme();
   const terminalThemes = useMemo(() => buildTerminalThemes(variant), [variant]);
-  const { subscribeTerminal, writeTerminal, resizeTerminal: resizeTerminalMux, openTerminal, status: muxStatus } = useMux();
+  const { subscribeTerminal, writeTerminal, resizeTerminal: resizeTerminalMux, openTerminal, closeTerminal, status: muxStatus } = useMux();
 
   const terminalRef = useRef<HTMLDivElement>(null);
   const terminalInstance = useRef<TerminalType | null>(null);
@@ -407,6 +373,7 @@ export function DirectTerminal({
           inputDisposable?.dispose();
           inputDisposable = null;
           unsubscribe?.();
+          closeTerminal(sessionId);
           terminal.dispose();
         };
       })
@@ -420,7 +387,7 @@ export function DirectTerminal({
       mounted = false;
       cleanup?.();
     };
-  }, [sessionId, variant, subscribeTerminal, writeTerminal, resizeTerminalMux, openTerminal]);
+  }, [sessionId, variant, subscribeTerminal, writeTerminal, resizeTerminalMux, openTerminal, closeTerminal]);
 
   // Live theme switching without terminal recreation
   useEffect(() => {

packages/web/src/components/__tests__/DirectTerminal.test.ts

@@ -1,66 +1,5 @@
 import { describe, it, expect } from "vitest";
-import { buildDirectTerminalWsUrl, buildTerminalThemes } from "@/components/DirectTerminal";
-
-describe("buildDirectTerminalWsUrl", () => {
-  it("keeps non-standard port when proxy path override is set", () => {
-    const wsUrl = buildDirectTerminalWsUrl({
-      location: {
-        protocol: "https:",
-        hostname: "example.com",
-        host: "example.com:8443",
-        port: "8443",
-      },
-      sessionId: "session-1",
-      proxyWsPath: "/ao-terminal-ws",
-    });
-
-    expect(wsUrl).toBe("wss://example.com:8443/ao-terminal-ws?session=session-1");
-  });
-
-  it("uses proxy path without port when default port is used", () => {
-    const wsUrl = buildDirectTerminalWsUrl({
-      location: {
-        protocol: "https:",
-        hostname: "example.com",
-        host: "example.com",
-        port: "",
-      },
-      sessionId: "session-2",
-      proxyWsPath: "/ao-terminal-ws",
-    });
-
-    expect(wsUrl).toBe("wss://example.com/ao-terminal-ws?session=session-2");
-  });
-
-  it("uses default path-based endpoint on standard ports when no proxy override is set", () => {
-    const wsUrl = buildDirectTerminalWsUrl({
-      location: {
-        protocol: "https:",
-        hostname: "example.com",
-        host: "example.com",
-        port: "443",
-      },
-      sessionId: "session-3",
-    });
-
-    expect(wsUrl).toBe("wss://example.com/ao-terminal-ws?session=session-3");
-  });
-
-  it("uses direct terminal port on non-standard ports when no proxy override is set", () => {
-    const wsUrl = buildDirectTerminalWsUrl({
-      location: {
-        protocol: "http:",
-        hostname: "localhost",
-        host: "localhost:3000",
-        port: "3000",
-      },
-      sessionId: "session-4",
-      directTerminalPort: "14888",
-    });
-
-    expect(wsUrl).toBe("ws://localhost:14888/ws?session=session-4");
-  });
-});
+import { buildTerminalThemes } from "@/components/DirectTerminal";
 
 const HEX_RE = /^#[0-9a-fA-F]{6}$/;
 const ANSI_KEYS = [

packages/web/src/hooks/useSessionEvents.ts

@@ -204,12 +204,18 @@ export function useSessionEvents(
     if (currentMembershipKey !== snapshotMembershipKey) {
       pendingMembershipKeyRef.current = snapshotMembershipKey;
       scheduleRefresh();
-      return;
-    }
-
-    if (Date.now() - lastRefreshAtRef.current >= STALE_REFRESH_INTERVAL_MS) {
+    } else if (Date.now() - lastRefreshAtRef.current >= STALE_REFRESH_INTERVAL_MS) {
       scheduleRefresh();
     }
+
+    return () => {
+      if (refreshTimerRef.current) {
+        clearTimeout(refreshTimerRef.current);
+        refreshTimerRef.current = null;
+      }
+      activeRefreshControllerRef.current?.abort();
+      activeRefreshControllerRef.current = null;
+    };
   }, [muxSessions, scheduleRefresh]);
 
   useEffect(() => {

packages/web/src/providers/MuxProvider.tsx

@@ -82,7 +82,6 @@ export function MuxProvider({ children }: { children: ReactNode }) {
   const reconnectAttempt = useRef(0);
   const reconnectTimer = useRef<ReturnType<typeof setTimeout> | null>(null);
   const runtimeConfigRef = useRef<{ directTerminalPort?: string; proxyWsPath?: string }>({});
-  const sessionSubscribedRef = useRef(false);
 
   const connect = useCallback(() => {
     if (wsRef.current) {
@@ -113,7 +112,6 @@ export function MuxProvider({ children }: { children: ReactNode }) {
         }
 
         // Always subscribe to sessions
-        sessionSubscribedRef.current = true;
         const subMsg: ClientMessage = {
           ch: "subscribe",
           topics: ["sessions"],
@@ -140,8 +138,9 @@ export function MuxProvider({ children }: { children: ReactNode }) {
               buffer.push(msg.data);
               buffersRef.current.set(msg.id, buffer);
 
+              const encoder = new TextEncoder();
               let bytes = bufferBytesRef.current.get(msg.id) ?? 0;
-              bytes += Buffer.byteLength(msg.data, "utf8");
+              bytes += encoder.encode(msg.data).length;
               bufferBytesRef.current.set(msg.id, bytes);
 
               // Trim buffer if needed (50KB limit)
@@ -149,7 +148,7 @@ export function MuxProvider({ children }: { children: ReactNode }) {
               if (bytes > RING_BUFFER_MAX) {
                 while (bytes > RING_BUFFER_MAX && buffer.length > 0) {
                   const removed = buffer.shift() ?? "";
-                  bytes -= Buffer.byteLength(removed, "utf8");
+                  bytes -= encoder.encode(removed).length;
                 }
                 bufferBytesRef.current.set(msg.id, bytes);
               }