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>

.gitignore

@@ -22,6 +22,12 @@ WestJeff*/
 # Offline packages (built by download-packages.sh)
 offline-packages/
 
+# Boot tool binaries (built by prepare-boot-tools.sh)
+boot-tools/
+
+# Deployment images (imported via webapp or USB)
+geastandardpbr/
+
 # OS files
 .DS_Store
 Thumbs.db