Add toram boot entry and Install to RAM resume support

- grub.cfg: add "load to RAM (toram)" entry to advanced submenu
- install_to_ram.go: resume from existing /dev/shm/bee-live copy if
  source medium is unavailable after bee-web restart
- tasks.go: fix "Recovered after bee-web restart" shown on every run
  (check j.lines before first append, not after)
- bee-install: retry unsquashfs up to 5x with wait-for-remount on
  source loss; clear error message with bee-remount-medium hint
- bee-remount-medium: new script to find and remount live ISO source
  after USB/CD reconnect; supports --wait polling mode
- 9000-bee-setup: chmod +x for bee-install and bee-remount-medium

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

iso/builder/config/hooks/normal/9000-bee-setup.hook.chroot

@@ -63,8 +63,10 @@ chmod +x /usr/local/bin/bee-sshsetup   2>/dev/null || true
 chmod +x /usr/local/bin/bee-smoketest  2>/dev/null || true
 chmod +x /usr/local/bin/bee            2>/dev/null || true
 chmod +x /usr/local/bin/bee-log-run    2>/dev/null || true
-chmod +x /usr/local/bin/bee-selfheal      2>/dev/null || true
-chmod +x /usr/local/bin/bee-boot-status  2>/dev/null || true
+chmod +x /usr/local/bin/bee-selfheal        2>/dev/null || true
+chmod +x /usr/local/bin/bee-boot-status    2>/dev/null || true
+chmod +x /usr/local/bin/bee-install        2>/dev/null || true
+chmod +x /usr/local/bin/bee-remount-medium 2>/dev/null || true
 if [ "$GPU_VENDOR" = "nvidia" ]; then
     chmod +x /usr/local/bin/bee-nvidia-load 2>/dev/null || true
     chmod +x /usr/local/bin/bee-gpu-burn 2>/dev/null || true