Address review findings in the app, server and tests

- app: startup shell, python and ssh probes run asynchronously so a slow
  shell profile can't freeze the window; PATH comes from the user's real
  login shell and a failed lookup isn't cached; a server that never
  answers is killed; the setup offer runs once per launch, only after the
  UI loads, and decides from HostName alone; connect.sh is started through
  `env ... zsh` so it works whatever the login shell is.
- server: volume validates the level before muting or changing anything.
- Steam: null-safe install-manager fields, http.client errors caught in
  store ratings, price fallback when a sale has no final price.
- tests: server output kept for diagnosis, any startup error retried, and
  captures asserted non-cacheable.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

scripts/push-vr-video.sh

@@ -0,0 +1,60 @@
+#!/usr/bin/env zsh
+# Mac-side: upload VR videos to the Steam Frame so DeoVR can play them in 3D.
+#
+# Files go to ~/Videos/VR on the Frame. The script links that folder into
+# DeoVR's Proton prefix as C:\users\steamuser\Videos\VR, so DeoVR's file
+# browser finds it under Videos. (It's also reachable as Z:\home\steamos\Videos\VR.)
+# Uploads resume if interrupted.
+#
+# Name files so DeoVR picks the projection: include _180 or _360 (or _fisheye190,
+# _mkx200, _rf52 ...) plus the stereo layout (_LR / _SBS side by side, _TB over-
+# under), e.g. "beach_180_LR.mp4". You can also change it in DeoVR's player.
+#
+# Usage:
+#   scripts/push-vr-video.sh FILE_OR_DIR...       # upload
+#   scripts/push-vr-video.sh --launch FILE...     # upload, then start DeoVR
+#   scripts/push-vr-video.sh --launch             # just start DeoVR
+#   scripts/push-vr-video.sh --list               # what's on the Frame
+set -euo pipefail
+
+FRAME_ALIAS=${FRAME_ALIAS:-frame}
+DEOVR_APPID=837380
+REMOTE_DIR="Videos/VR"
+PREFIX_VIDEOS=".local/share/Steam/steamapps/compatdata/$DEOVR_APPID/pfx/drive_c/users/steamuser/Videos"
+
+launch=0 list=0
+while (( $# )); do
+  case "$1" in
+    -h|--help) sed -n '2,18p' "$0"; exit 0 ;;
+    --launch)  launch=1; shift ;;
+    --list)    list=1; shift ;;
+    --)        shift; break ;;
+    -*)        print -u2 "push-vr-video: unknown option $1"; exit 2 ;;
+    *)         break ;;
+  esac
+done
+(( $# || launch || list )) || { sed -n '2,18p' "$0"; exit 2; }
+
+for f in "$@"; do
+  [[ -e "$f" ]] || { print -u2 "push-vr-video: no such file: $f"; exit 2; }
+done
+
+# Create the folder and link it into DeoVR's prefix (the prefix exists once
+# DeoVR has run). Never replace a real directory that's already there.
+ssh "$FRAME_ALIAS" "mkdir -p ~/$REMOTE_DIR
+p=~/$PREFIX_VIDEOS
+if [ -d \"\$p\" ] && [ ! -e \"\$p/VR\" ]; then ln -s ~/$REMOTE_DIR \"\$p/VR\"; fi
+[ -d \"\$p\" ] || echo 'note: DeoVR has not run yet; use Z:\\home\\steamos\\Videos\\VR or run this again after starting it once' >&2"
+
+if (( $# )); then
+  rsync -a --partial --progress "$@" "$FRAME_ALIAS:$REMOTE_DIR/"
+fi
+
+if (( list )); then
+  ssh "$FRAME_ALIAS" "cd ~/$REMOTE_DIR && ls -lhR"
+fi
+
+if (( launch )); then
+  ssh "$FRAME_ALIAS" "steam steam://rungameid/$DEOVR_APPID >/dev/null 2>&1 &"
+  print "DeoVR starting on the Frame. Open Local files / the file browser → Videos → VR."
+fi