Refactor: consolidate ID generation and shared helpers (bd-0702, bd-1445)

- Created ids.go with ValidateIssueIDPrefix, GenerateIssueID, EnsureIDs
- Created issues.go with insertIssue/insertIssues helpers
- Created events_helpers.go with recordCreatedEvent/recordCreatedEvents
- Created dirty_helpers.go with markDirty/markDirtyBatch
- Refactored sqlite.go and batch_ops.go to use new helpers
- Removed duplicate code from hash_ids.go

Amp-Thread-ID: https://ampcode.com/threads/T-b1ab5a16-96de-4e4d-b255-3617055a89eb
Co-authored-by: Amp <amp@ampcode.com>

internal/storage/sqlite/issues.go

@@ -0,0 +1,59 @@
+package sqlite
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+
+	"github.com/steveyegge/beads/internal/types"
+)
+
+// insertIssue inserts a single issue into the database
+func insertIssue(ctx context.Context, conn *sql.Conn, issue *types.Issue) error {
+	_, err := conn.ExecContext(ctx, `
+		INSERT INTO issues (
+			id, content_hash, title, description, design, acceptance_criteria, notes,
+			status, priority, issue_type, assignee, estimated_minutes,
+			created_at, updated_at, closed_at, external_ref
+		) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+	`,
+		issue.ID, issue.ContentHash, issue.Title, issue.Description, issue.Design,
+		issue.AcceptanceCriteria, issue.Notes, issue.Status,
+		issue.Priority, issue.IssueType, issue.Assignee,
+		issue.EstimatedMinutes, issue.CreatedAt, issue.UpdatedAt,
+		issue.ClosedAt, issue.ExternalRef,
+	)
+	if err != nil {
+		return fmt.Errorf("failed to insert issue: %w", err)
+	}
+	return nil
+}
+
+// insertIssues bulk inserts multiple issues using a prepared statement
+func insertIssues(ctx context.Context, conn *sql.Conn, issues []*types.Issue) error {
+	stmt, err := conn.PrepareContext(ctx, `
+		INSERT INTO issues (
+			id, content_hash, title, description, design, acceptance_criteria, notes,
+			status, priority, issue_type, assignee, estimated_minutes,
+			created_at, updated_at, closed_at, external_ref
+		) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+	`)
+	if err != nil {
+		return fmt.Errorf("failed to prepare statement: %w", err)
+	}
+	defer func() { _ = stmt.Close() }()
+
+	for _, issue := range issues {
+		_, err = stmt.ExecContext(ctx,
+			issue.ID, issue.ContentHash, issue.Title, issue.Description, issue.Design,
+			issue.AcceptanceCriteria, issue.Notes, issue.Status,
+			issue.Priority, issue.IssueType, issue.Assignee,
+			issue.EstimatedMinutes, issue.CreatedAt, issue.UpdatedAt,
+			issue.ClosedAt, issue.ExternalRef,
+		)
+		if err != nil {
+			return fmt.Errorf("failed to insert issue %s: %w", issue.ID, err)
+		}
+	}
+	return nil
+}