Document iteration 1: settings file, HA Dashboard tab, new hooks

README: settings file, --config, the new tab. ARCHITECTURE.md and
CLAUDE.md: prepare() hook, app command-line options, app code layout,
WebEngine notes, the moc raw-string pitfall. THIRD_PARTY_NOTICES: Qt
WebEngine. Ship config.example.json; the package README explains the
set-up. PROGRESS.md and DESIGN.md: phase 3 results and deviations.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

scripts/package-release.sh

@@ -81,6 +81,14 @@ chmod +x "$out/install.sh" "$out/uninstall.sh"
         echo "SteamOS update, use the -bundled package instead."
     fi
     echo
+    echo "Settings (required before the first start):"
+    echo "                   mkdir -p ~/.config/$project"
+    echo "                   cp share/$project/config.example.json ~/.config/$project/config.json"
+    echo "                   chmod 600 ~/.config/$project/config.json"
+    echo "                   then edit it (device name, MQTT broker, Home Assistant URL)."
+    echo "                   Without valid settings the app exits; to see why, run"
+    echo "                   ./bin/$exe --desktop in a terminal."
+    echo
     echo "Install / update:  ./install.sh     (SteamVR must be running)"
     echo "                   SteamVR remembers this folder's location: after moving it,"
     echo "                   run ./install.sh again."