(Reuters) – British greeting cards retailer Card Factory forecast annual core earnings ahead of market expectations on Tuesday as people rushed to its high-street stores to buy Christmas cards amid strikes at Royal Mail, which hurt online sales. The company expects full-year core earnings to be at least 106 million pounds ($128.8 million), compared with analysts’ current consensus of 96.9 million pounds. Sales jumped more than 28% to 432.6 million pounds in the 11 months ended Dec. 31, while like-for-like store revenue grew 7%, helped by strong Christmas trading and value offerings. The retail…