Polish Huddle voice controls (#4694)

## Summary

- add a visible Stop control for interrupting agent speech
- make push-to-talk available by default while preserving manual mute
controls
- refine agent management, muted audio states, drawer layering, and
return navigation
- suppress duplicate notification sounds for Huddle messages

## Why

Huddles could trap users behind long agent speech, hide useful agent
controls, and leave temporary Huddle state visible after the call. The
drawer also regressed when the terminal substrate began painting behind
the rounded app surface.

## Validation

- `just desktop-ci`
- focused Huddle Playwright coverage for the drawer, speech
interruption, agent picker, and leave navigation

---------

Signed-off-by: kenny lopez <klopez4212@gmail.com>
Signed-off-by: Wes <wesbillman@users.noreply.github.com>
Co-authored-by: Wes <wesbillman@users.noreply.github.com>
Co-authored-by: Carl <c7ebe626f000404285d3686e1dc74cc07cc60a9754a150041ba132e14bd3e2ec@buzz.block.builderlab.xyz>

desktop/src/app/useAppShellDesktopNotifications.ts

@@ -20,6 +20,7 @@ import {
 import {
   playNotificationSound,
   resolveSlotSound,
+  shouldPlayNotificationSound,
 } from "@/features/notifications/lib/sound";
 import type { Channel, RelayEvent } from "@/shared/api/types";
 
@@ -31,6 +32,7 @@ export function useAppShellDesktopNotifications({
   notificationSettings,
   openSearchHit,
   pubkey,
+  silentChannelIds,
 }: {
   channels: Channel[];
   enabled: boolean;
@@ -41,6 +43,7 @@ export function useAppShellDesktopNotifications({
     hit: import("@/shared/api/types").SearchHit,
   ) => Promise<unknown>;
   pubkey?: string;
+  silentChannelIds?: ReadonlySet<string>;
 }) {
   const handleChannelNotification = React.useEffectEvent(
     (_channelId: string, event: RelayEvent) => {
@@ -80,7 +83,9 @@ export function useAppShellDesktopNotifications({
         },
       }).then((didSend) => {
         if (!didSend) return;
-        playNotificationSound(resolveSlotSound(notificationSettings, "dm"));
+        if (shouldPlayNotificationSound(channel.id, silentChannelIds)) {
+          playNotificationSound(resolveSlotSound(notificationSettings, "dm"));
+        }
         void requestDockBounce();
       });
     },
@@ -126,9 +131,11 @@ export function useAppShellDesktopNotifications({
         },
       }).then((didSend) => {
         if (!didSend) return;
-        playNotificationSound(
-          resolveSlotSound(notificationSettings, "thread_reply"),
-        );
+        if (shouldPlayNotificationSound(channelId, silentChannelIds)) {
+          playNotificationSound(
+            resolveSlotSound(notificationSettings, "thread_reply"),
+          );
+        }
         void requestDockBounce();
       });
     },