improve stream sidebar experience and avatar affordance (#284)

* fix awkward stream list experience

* fix avatar change affordance

* cleanup unnecessary logic

* cleanup unnecessary logic and complexity

* unused var

js/desktop/src/hooks/use-stream-view-mode.ts

@@ -1,41 +1,12 @@
 import { useCallback, useState } from 'react';
-import type { Particle } from '@/api/types';
 
 export type StreamViewMode = 'player' | 'list';
 
-function decideMode(
-  streamParticle: Particle & { type: 'stream' },
-  userId: string | undefined,
-): StreamViewMode {
-  const marker = userId ? streamParticle.playback_markers?.[userId] : undefined;
-  const lastChildAt = streamParticle.last_child_created_at;
-  const caughtUp =
-    !!marker && !!lastChildAt && lastChildAt.getTime() <= marker.getTime();
-  return caughtUp ? 'list' : 'player';
-}
-
-/**
- * Which mode a stream opens in: the player (autoplay catch-up) when there's
- * unseen content, the browsable list when the user is fully caught up.
- * Decided once on entry from the playback marker vs. the stream's last
- * activity — browsing afterwards advances the marker, but the mode only
- * changes via the user's toggle.
- */
-export function useStreamViewMode(
-  streamParticle: Particle & { type: 'stream' },
-  userId: string | undefined,
-): { mode: StreamViewMode; toggle: () => void } {
-  const [mode, setMode] = useState<StreamViewMode>(() =>
-    decideMode(streamParticle, userId),
-  );
-
-  // Re-decide when navigating between streams without an unmount.
-  const [prevStreamId, setPrevStreamId] = useState(streamParticle.id);
-  if (prevStreamId !== streamParticle.id) {
-    setPrevStreamId(streamParticle.id);
-    setMode(decideMode(streamParticle, userId));
-  }
-
+export function useStreamViewMode(): {
+  mode: StreamViewMode;
+  toggle: () => void;
+} {
+  const [mode, setMode] = useState<StreamViewMode>('player');
   const toggle = useCallback(() => {
     setMode((prev) => (prev === 'player' ? 'list' : 'player'));
   }, []);