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/overlay/usr/local/bin/bee-install

@@ -65,6 +65,9 @@ done
 SQUASHFS="/run/live/medium/live/filesystem.squashfs"
 if [ ! -f "$SQUASHFS" ]; then
     echo "ERROR: squashfs not found at $SQUASHFS" >&2
+    echo "  The live medium may have been disconnected." >&2
+    echo "  Reconnect the disc and run:  bee-remount-medium --wait" >&2
+    echo "  Then re-run bee-install." >&2
     exit 1
 fi
 
@@ -162,10 +165,59 @@ log "  Mounted."
 log "--- Step 5/7: Unpacking filesystem (this takes 10-20 minutes) ---"
 log "  Source: $SQUASHFS"
 log "  Target: $MOUNT_ROOT"
-unsquashfs -f -d "$MOUNT_ROOT" "$SQUASHFS" 2>&1 | \
-    grep -E '^\[|^inod|^created|^extract' | \
-    while read -r line; do log "  $line"; done || true
-log "  Unpack complete."
+
+# unsquashfs does not support resume, so retry the entire unpack step if the
+# source medium disappears mid-copy (e.g. CD physically disconnected).
+UNPACK_ATTEMPTS=0
+UNPACK_MAX=5
+while true; do
+    UNPACK_ATTEMPTS=$(( UNPACK_ATTEMPTS + 1 ))
+    if [ "$UNPACK_ATTEMPTS" -gt "$UNPACK_MAX" ]; then
+        die "Unpack failed $UNPACK_MAX times — giving up. Check the disc and logs."
+    fi
+    [ "$UNPACK_ATTEMPTS" -gt 1 ] && log "  Retry attempt $UNPACK_ATTEMPTS / $UNPACK_MAX ..."
+
+    # Re-check squashfs is reachable before each attempt
+    if [ ! -f "$SQUASHFS" ]; then
+        log "  SOURCE LOST: $SQUASHFS not found."
+        log "  Reconnect the disc and run 'bee-remount-medium --wait' in another terminal,"
+        log "  then press Enter here to retry."
+        read -r _
+        continue
+    fi
+
+    # wipe partial unpack so unsquashfs starts clean
+    if [ "$UNPACK_ATTEMPTS" -gt 1 ]; then
+        log "  Cleaning partial unpack from $MOUNT_ROOT ..."
+        # keep the mount point itself but remove its contents
+        find "$MOUNT_ROOT" -mindepth 1 -maxdepth 1 -exec rm -rf {} + 2>/dev/null || true
+    fi
+
+    UNPACK_OK=0
+    unsquashfs -f -d "$MOUNT_ROOT" "$SQUASHFS" 2>&1 | \
+        grep -E '^\[|^inod|^created|^extract|^ERROR|failed' | \
+        while IFS= read -r line; do log "  $line"; done || UNPACK_OK=$?
+
+    # Check squashfs is still reachable (gone = disc pulled during copy)
+    if [ ! -f "$SQUASHFS" ]; then
+        log "  WARNING: source medium lost during unpack — will retry after remount."
+        log "  Run 'bee-remount-medium --wait' in another terminal, then press Enter."
+        read -r _
+        continue
+    fi
+
+    # Verify the unpack produced a usable root (presence of /etc is a basic check)
+    if [ -d "${MOUNT_ROOT}/etc" ]; then
+        log "  Unpack complete."
+        break
+    else
+        log "  WARNING: unpack produced no /etc — squashfs may be corrupt or incomplete."
+        if [ "$UNPACK_ATTEMPTS" -lt "$UNPACK_MAX" ]; then
+            log "  Retrying in 5 s ..."
+            sleep 5
+        fi
+    fi
+done
 
 # ------------------------------------------------------------------
 log "--- Step 6/7: Configuring installed system ---"