Add git notes preservation system with backup/restore functionality

- Added WarnAboutGitNotesLoss hook that warns before destructive git operations
- Implemented comprehensive backup/restore system for conversation notes
- Added CLI commands: hooks notes backup/restore/list
- Configured git to automatically copy notes during rebase operations
- Created backup.go with full notes backup and restoration functionality

This ensures conversation context is never lost during rebasing, squashing, or other destructive git operations.

cmd/notes.go

@@ -0,0 +1,115 @@
+package cmd
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/imjasonh/hooks/internal/notes"
+	"github.com/spf13/cobra"
+)
+
+var notesCmd = &cobra.Command{
+	Use:   "notes",
+	Short: "Manage git notes backups and restoration",
+	Long:  `Commands for backing up, restoring, and managing Claude conversation notes.`,
+}
+
+var backupCmd = &cobra.Command{
+	Use:   "backup [filename]",
+	Short: "Backup all conversation notes to a JSON file",
+	Long: `Creates a backup of all conversation notes attached to commits.
+If no filename is provided, creates a timestamped backup file.`,
+	Args: cobra.MaximumNArgs(1),
+	RunE: func(cmd *cobra.Command, args []string) error {
+		ctx := context.Background()
+		notesManager := notes.NewNotesManager(".")
+
+		var filename string
+		if len(args) > 0 {
+			filename = args[0]
+		} else {
+			var err error
+			filename, err = notesManager.CreateRebaseBackup(ctx)
+			if err != nil {
+				return fmt.Errorf("failed to create backup: %w", err)
+			}
+		}
+
+		backup, err := notesManager.BackupAllNotes(ctx)
+		if err != nil {
+			return fmt.Errorf("failed to backup notes: %w", err)
+		}
+
+		if err := notesManager.SaveBackupToFile(backup, filename); err != nil {
+			return fmt.Errorf("failed to save backup file: %w", err)
+		}
+
+		fmt.Printf("✅ Backed up %d conversation notes to %s\n", len(backup.Notes), filename)
+		return nil
+	},
+}
+
+var restoreCmd = &cobra.Command{
+	Use:   "restore <filename>",
+	Short: "Restore conversation notes from a backup file",
+	Long: `Restores conversation notes from a previously created backup file.
+Only restores notes for commits that still exist and don't already have notes.`,
+	Args: cobra.ExactArgs(1),
+	RunE: func(cmd *cobra.Command, args []string) error {
+		ctx := context.Background()
+		notesManager := notes.NewNotesManager(".")
+
+		filename := args[0]
+		backup, err := notesManager.LoadBackupFromFile(filename)
+		if err != nil {
+			return fmt.Errorf("failed to load backup file: %w", err)
+		}
+
+		fmt.Printf("📄 Loaded backup from %s (%d notes, created %s)\n",
+			filename, len(backup.Notes), backup.BackupTime.Format("2006-01-02 15:04:05"))
+
+		if err := notesManager.RestoreNotesFromBackup(ctx, backup); err != nil {
+			return fmt.Errorf("failed to restore notes: %w", err)
+		}
+
+		return nil
+	},
+}
+
+var listCmd = &cobra.Command{
+	Use:   "list",
+	Short: "List all commits with conversation notes",
+	Long:  `Shows all commits that have conversation notes attached.`,
+	RunE: func(cmd *cobra.Command, args []string) error {
+		ctx := context.Background()
+		notesManager := notes.NewNotesManager(".")
+
+		backup, err := notesManager.BackupAllNotes(ctx)
+		if err != nil {
+			return fmt.Errorf("failed to list notes: %w", err)
+		}
+
+		if len(backup.Notes) == 0 {
+			fmt.Println("No conversation notes found.")
+			return nil
+		}
+
+		fmt.Printf("Found %d commits with conversation notes:\n\n", len(backup.Notes))
+		for commitHash, note := range backup.Notes {
+			// Get commit subject
+			fmt.Printf("• %s (%s)\n", commitHash[:8], note.Timestamp.Format("2006-01-02 15:04"))
+			fmt.Printf("  Session: %s\n", note.SessionID)
+			fmt.Printf("  Tools: %v\n\n", note.ToolsUsed)
+		}
+
+		fmt.Printf("💡 View notes with: git notes --ref=claude-conversations show <commit>\n")
+		return nil
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(notesCmd)
+	notesCmd.AddCommand(backupCmd)
+	notesCmd.AddCommand(restoreCmd)
+	notesCmd.AddCommand(listCmd)
+}