Add snapshot-based LVM migration scripts

- snapshot_migrate_to_internal.sh: Complete snapshot-based migration from external M.2 to internal NVMe
- preview_snapshot_migration.sh: Preview script showing snapshot migration process
- migrate_lvm_to_internal.sh: Alternative rsync-based migration script
- preview_migration.sh: Preview for rsync-based migration

Key features:
- LVM snapshot creation of ALL logical volumes (root, home, boot, swap)
- Block-level dd copying for exact system clone
- Automatic LVM structure setup on internal drive
- GRUB/EFI boot configuration
- Future snapshot management tools
- Space-efficient one-at-a-time processing

Migration preserves complete live system state with bit-perfect accuracy.

preview_migration.sh

@@ -0,0 +1,75 @@
+#!/bin/bash
+
+# LVM Migration Preview Script
+# Shows current status and what the migration will do
+
+set -euo pipefail
+
+# Colors
+GREEN='\033[0;32m'
+YELLOW='\033[1;33m'
+BLUE='\033[0;34m'
+RED='\033[0;31m'
+NC='\033[0m'
+
+echo -e "${BLUE}=== LVM Migration Preview ===${NC}"
+echo
+
+echo -e "${GREEN}Current Boot Status:${NC}"
+echo "Root mounted from: $(findmnt -n -o SOURCE /)"
+echo "Boot mounted from: $(findmnt -n -o SOURCE /boot)"
+echo "Home mounted from: $(findmnt -n -o SOURCE /home)"
+echo
+
+echo -e "${GREEN}Current LVM Structure (External M.2):${NC}"
+sudo vgs migration-vg 2>/dev/null || echo "No VG found"
+echo
+sudo lvs migration-vg 2>/dev/null || echo "No LVs found"
+echo
+
+echo -e "${GREEN}Current Drive Layout:${NC}"
+echo "External M.2 (sda):"
+lsblk /dev/sda
+echo
+echo "Internal NVMe (nvme0n1):"
+lsblk /dev/nvme0n1
+echo
+
+echo -e "${GREEN}Available Space Analysis:${NC}"
+echo "External VG size: $(sudo vgs --noheadings --units g -o vg_size migration-vg | tr -d ' ')B"
+echo "External VG free: $(sudo vgs --noheadings --units g -o vg_free migration-vg | tr -d ' ')B"
+echo "Internal drive size: $(lsblk -b -n -o SIZE /dev/nvme0n1 | awk '{printf "%.1fGB", $1/1024/1024/1024}')"
+echo
+
+echo -e "${YELLOW}Migration Plan:${NC}"
+echo "1. ✅ Wipe internal NVMe drive completely"
+echo "2. ✅ Create new GPT partition table"
+echo "3. ✅ Create EFI boot partition (512MB)"
+echo "4. ✅ Create LVM partition (remaining space)"
+echo "5. ✅ Set up LVM with volume group 'internal-vg'"
+echo "6. ✅ Create logical volumes matching current structure"
+echo "7. ✅ Copy all data from external to internal"
+echo "8. ✅ Configure GRUB for LVM boot"
+echo "9. ✅ Set up LVM snapshot capabilities"
+echo "10. ✅ Reserve 20% space for snapshots"
+echo
+
+echo -e "${RED}⚠️  WARNINGS:${NC}"
+echo "• This will COMPLETELY WIPE the internal NVMe drive"
+echo "• All current data on internal drive will be lost"
+echo "• Make sure you're booted from external M.2 (verified above)"
+echo "• Ensure external M.2 LED is active/blinking"
+echo
+
+echo -e "${GREEN}Snapshot Features After Migration:${NC}"
+echo "• lvm-snapshot-manager create     - Create system snapshots"
+echo "• lvm-snapshot-manager list       - List existing snapshots"
+echo "• lvm-snapshot-manager remove     - Remove snapshots"
+echo "• lvm-snapshot-manager merge      - Restore from snapshot"
+echo "• snapshot-backup                 - Backup using snapshots"
+echo
+
+echo -e "${BLUE}Ready to proceed?${NC}"
+echo "Run: sudo ./migrate_lvm_to_internal.sh"
+echo
+echo -e "${YELLOW}Estimated time: 2-4 hours depending on data size${NC}"