Add multi-boot PXE menu, Clonezilla backup management, and GE Aerospace branding

- iPXE boot menu with WinPE, Clonezilla, Blancco Drive Eraser, Memtest86+
- prepare-boot-tools.sh to download/extract boot tool binaries
- Clonezilla backup management in webapp (upload, download, delete)
- Clonezilla Samba share for network backup/restore
- GE Aerospace logo and favicon in webapp
- Updated playbook with boot tool directories and webapp env vars

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

build-usb.sh

@@ -185,6 +185,16 @@ if [ -d "$WEBAPP_DIR" ]; then
     echo "    Copied webapp/"
 fi
 
+# Copy boot tools (Clonezilla, Blancco, Memtest) if prepared
+BOOT_TOOLS_DIR="$SCRIPT_DIR/boot-tools"
+if [ -d "$BOOT_TOOLS_DIR" ]; then
+    cp -r "$BOOT_TOOLS_DIR" "$MOUNT_POINT/boot-tools"
+    TOOLS_SIZE=$(du -sh "$MOUNT_POINT/boot-tools" | cut -f1)
+    echo "    Copied boot-tools/ ($TOOLS_SIZE)"
+else
+    echo "    No boot-tools/ found (run prepare-boot-tools.sh first)"
+fi
+
 # Optionally copy WinPE deployment images
 if [ -n "$WINPE_SOURCE" ] && [ -d "$WINPE_SOURCE" ]; then
     echo "    Copying WinPE deployment content from $WINPE_SOURCE..."