Add curl-based Frame Home installer

Add a Steam Frame bootstrap that downloads and validates the selected release installer,
then runs the existing payload installer. Document latest and versioned install commands.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

frame/install-frame-home-online.sh

@@ -0,0 +1,38 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+if [[ "$(uname -m)" != aarch64 ]]; then
+    echo "Frame Home must be installed on the Steam Frame (ARM64)." >&2
+    exit 1
+fi
+
+for tool in curl unzip; do
+    command -v "$tool" >/dev/null 2>&1 || {
+        echo "Missing required command: $tool" >&2
+        exit 1
+    }
+done
+
+tag=${FRAME_HOME_TAG:-latest}
+if [[ -z "$tag" || "$tag" == *[^a-zA-Z0-9._-]* ]]; then
+    echo "Invalid release tag: $tag" >&2
+    exit 1
+fi
+
+url="https://github.com/Toastconcern/FrameStudio/releases/download/$tag/FrameHome-installer.zip"
+tmp=$(mktemp -d "${TMPDIR:-/tmp}/frame-home-install.XXXXXXXX")
+trap 'rm -rf "$tmp"' EXIT
+
+archive="$tmp/FrameHome-installer.zip"
+echo "Downloading Frame Home release $tag..."
+curl --fail --location --silent --show-error --retry 2 --output "$archive" "$url"
+unzip -tq "$archive"
+unzip -q "$archive" -d "$tmp"
+
+installer="$tmp/FrameHome-installer/payload"
+if [[ ! -f "$installer/install.sh" || ! -x "$installer/bin/frame-home" ]]; then
+    echo "The downloaded release does not contain a valid Frame Home installer." >&2
+    exit 1
+fi
+
+sh "$installer/install.sh" "$@"