Well, it's actually literally 'good luck' (mazal means luck, tov means good)
Stars are 'kochavim', the 'ch' being a guttral ch as in the Scottish 'loch'. But yes, colloquially it's entirely synonymous with congratulations.
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Hampster Squared has stuff at www.tilla.co.uk, Tue 21 Jul 2009, 16:58,
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