feat(storage): add Dolt backend for version-controlled issue storage

Implements a complete Dolt storage backend that mirrors the SQLite implementation
with MySQL-compatible syntax and adds version control capabilities.

Key features:
- Full Storage interface implementation (~50 methods)
- Version control operations: commit, push, pull, branch, merge, checkout
- History queries via AS OF and dolt_history_* tables
- Cell-level merge instead of line-level JSONL merge
- SQL injection protection with input validation

Bug fixes applied during implementation:
- Added missing quality_score, work_type, source_system to scanIssue
- Fixed Status() to properly parse boolean staged column
- Added validation to CreateIssues (was missing in batch create)
- Made RenameDependencyPrefix transactional
- Expanded GetIssueHistory to return more complete data

Test coverage: 17 tests covering CRUD, dependencies, labels, search,
comments, events, statistics, and SQL injection protection.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

internal/storage/dolt/rename.go

@@ -0,0 +1,129 @@
+package dolt
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/steveyegge/beads/internal/types"
+)
+
+// UpdateIssueID updates an issue ID and all its references
+func (s *DoltStore) UpdateIssueID(ctx context.Context, oldID, newID string, issue *types.Issue, actor string) error {
+	tx, err := s.db.BeginTx(ctx, nil)
+	if err != nil {
+		return fmt.Errorf("failed to begin transaction: %w", err)
+	}
+	defer func() { _ = tx.Rollback() }()
+
+	// Update the issue itself
+	result, err := tx.ExecContext(ctx, `
+		UPDATE issues
+		SET id = ?, title = ?, description = ?, design = ?, acceptance_criteria = ?, notes = ?, updated_at = ?
+		WHERE id = ?
+	`, newID, issue.Title, issue.Description, issue.Design, issue.AcceptanceCriteria, issue.Notes, time.Now(), oldID)
+	if err != nil {
+		return fmt.Errorf("failed to update issue ID: %w", err)
+	}
+
+	rows, err := result.RowsAffected()
+	if err != nil {
+		return fmt.Errorf("failed to get rows affected: %w", err)
+	}
+	if rows == 0 {
+		return fmt.Errorf("issue not found: %s", oldID)
+	}
+
+	// Update references in dependencies
+	_, err = tx.ExecContext(ctx, `UPDATE dependencies SET issue_id = ? WHERE issue_id = ?`, newID, oldID)
+	if err != nil {
+		return fmt.Errorf("failed to update issue_id in dependencies: %w", err)
+	}
+
+	_, err = tx.ExecContext(ctx, `UPDATE dependencies SET depends_on_id = ? WHERE depends_on_id = ?`, newID, oldID)
+	if err != nil {
+		return fmt.Errorf("failed to update depends_on_id in dependencies: %w", err)
+	}
+
+	// Update references in events
+	_, err = tx.ExecContext(ctx, `UPDATE events SET issue_id = ? WHERE issue_id = ?`, newID, oldID)
+	if err != nil {
+		return fmt.Errorf("failed to update events: %w", err)
+	}
+
+	// Update references in labels
+	_, err = tx.ExecContext(ctx, `UPDATE labels SET issue_id = ? WHERE issue_id = ?`, newID, oldID)
+	if err != nil {
+		return fmt.Errorf("failed to update labels: %w", err)
+	}
+
+	// Update references in comments
+	_, err = tx.ExecContext(ctx, `UPDATE comments SET issue_id = ? WHERE issue_id = ?`, newID, oldID)
+	if err != nil {
+		return fmt.Errorf("failed to update comments: %w", err)
+	}
+
+	// Update dirty_issues
+	_, err = tx.ExecContext(ctx, `
+		INSERT INTO dirty_issues (issue_id, marked_at)
+		VALUES (?, ?)
+		ON DUPLICATE KEY UPDATE marked_at = VALUES(marked_at)
+	`, newID, time.Now())
+	if err != nil {
+		return fmt.Errorf("failed to mark issue dirty: %w", err)
+	}
+
+	// Delete old dirty entry
+	_, err = tx.ExecContext(ctx, `DELETE FROM dirty_issues WHERE issue_id = ?`, oldID)
+	if err != nil {
+		return fmt.Errorf("failed to delete old dirty entry: %w", err)
+	}
+
+	// Record rename event
+	_, err = tx.ExecContext(ctx, `
+		INSERT INTO events (issue_id, event_type, actor, old_value, new_value)
+		VALUES (?, 'renamed', ?, ?, ?)
+	`, newID, actor, oldID, newID)
+	if err != nil {
+		return fmt.Errorf("failed to record rename event: %w", err)
+	}
+
+	return tx.Commit()
+}
+
+// RenameDependencyPrefix updates the prefix in all dependency records
+func (s *DoltStore) RenameDependencyPrefix(ctx context.Context, oldPrefix, newPrefix string) error {
+	tx, err := s.db.BeginTx(ctx, nil)
+	if err != nil {
+		return fmt.Errorf("failed to begin transaction: %w", err)
+	}
+	defer func() { _ = tx.Rollback() }()
+
+	// Update issue_id column
+	_, err = tx.ExecContext(ctx, `
+		UPDATE dependencies
+		SET issue_id = CONCAT(?, SUBSTRING(issue_id, LENGTH(?) + 1))
+		WHERE issue_id LIKE CONCAT(?, '%')
+	`, newPrefix, oldPrefix, oldPrefix)
+	if err != nil {
+		return fmt.Errorf("failed to update issue_id in dependencies: %w", err)
+	}
+
+	// Update depends_on_id column
+	_, err = tx.ExecContext(ctx, `
+		UPDATE dependencies
+		SET depends_on_id = CONCAT(?, SUBSTRING(depends_on_id, LENGTH(?) + 1))
+		WHERE depends_on_id LIKE CONCAT(?, '%')
+	`, newPrefix, oldPrefix, oldPrefix)
+	if err != nil {
+		return fmt.Errorf("failed to update depends_on_id in dependencies: %w", err)
+	}
+
+	return tx.Commit()
+}
+
+// RenameCounterPrefix is a no-op with hash-based IDs
+func (s *DoltStore) RenameCounterPrefix(ctx context.Context, oldPrefix, newPrefix string) error {
+	// Hash-based IDs don't use counters
+	return nil
+}