feat: include SSH helper binaries in Linux packages (#268)

* feat: copy SSH helper binaries from upstream installer

The upstream Claude Desktop now ships SSH helper binaries in
resources/claude-ssh/. Copy the architecture-matching Linux binary
and version.txt into the Electron resources directory during build,
enabling SSH mode support in Linux packages.

Only the binary for the target architecture is included to avoid
shipping unnecessary ~6MB binaries for other platforms/arches.

Refs #249

Co-Authored-By: Claude <claude@anthropic.com>

* refactor: simplify copy_ssh_helpers by removing redundant checks

The file existence checks after `cp ... || exit 1` were unreachable
dead code — if cp fails, the script already exits. Also quote the
variable in the -d test for style guide consistency.

Co-Authored-By: Claude <claude@anthropic.com>

---------

Co-authored-by: Claude <claude@anthropic.com>

build.sh

@@ -1289,6 +1289,31 @@ copy_locale_files() {
 	echo "app.asar processed and staged in $app_staging_dir"
 }
 
+copy_ssh_helpers() {
+	section_header 'SSH Helpers'
+
+	local ssh_src="$claude_extract_dir/lib/net45/resources/claude-ssh"
+	local ssh_dest="$electron_resources_dest/claude-ssh"
+	local binary_name="claude-ssh-linux-$architecture"
+
+	if [[ ! -d "$ssh_src" ]]; then
+		echo "Warning: SSH helpers not found at $ssh_src"
+		section_footer 'SSH Helpers'
+		return
+	fi
+
+	mkdir -p "$ssh_dest" || exit 1
+	cp "$ssh_src/version.txt" "$ssh_dest/" || exit 1
+	cp "$ssh_src/$binary_name" "$ssh_dest/" || exit 1
+	chmod +x "$ssh_dest/$binary_name"
+
+	echo "Copied SSH helper files:"
+	echo "  version.txt"
+	echo "  $binary_name"
+
+	section_footer 'SSH Helpers'
+}
+
 #===============================================================================
 # Packaging Functions
 #===============================================================================
@@ -1481,6 +1506,7 @@ main() {
 	stage_electron
 	process_icons
 	copy_locale_files
+	copy_ssh_helpers
 
 	cd "$project_root" || exit 1