feat(installer): add 'Install to disk' in Tools submenu

Copies the live system to a local disk via unsquashfs — no debootstrap,
no network required. Supports UEFI (GPT+EFI) and BIOS (MBR) layouts.

ISO:
- Add squashfs-tools, parted, grub-pc, grub-efi-amd64 to package list
- New overlay script bee-install: partitions, formats, unsquashfs,
  writes fstab, runs grub-install+update-grub in chroot

Go TUI:
- Settings → Tools submenu (Install to disk, Check tools)
- Disk picker screen: lists non-USB, non-boot disks via lsblk
- Confirm screen warns about data loss
- Runs with live progress tail of /tmp/bee-install.log
- platform/install.go: ListInstallDisks, InstallToDisk, findLiveBootDevice

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

audit/internal/tui/view.go

@@ -76,6 +76,10 @@ func (m model) View() string {
 			)
 		case screenInterfacePick:
 			body = renderMenu("Interfaces", "Select interface", renderInterfaceItems(m.interfaces), m.cursor)
+		case screenTools:
+			body = renderMenu("Tools", "Select action", m.toolsMenu, m.cursor)
+		case screenInstallDiskPick:
+			body = renderInstallDiskPick(m)
 		case screenStaticForm:
 			body = renderForm("Static IPv4: "+m.selectedIface, m.formFields, m.formIndex)
 		case screenConfirm: