OTTAWA—Inequality is fast shaping up to be a key focus of the federal NDP policy convention as thousands of New Democrats prepare to gather online this afternoon to kick off the three-day event. Party members cast their votes recently to whittle down hundreds of proposed resolutions into a short list whose top policies include a $15 federal minimum wage and a call to “abolish billionaires” and for-profit long-term care. Delegates also have the opportunity to insert the word “socialism” into the party constitution after members voted to scrub it from the preamble in 2013 under then-leader Thomas Mulcair. The term, once a nearly taboo descriptor in federal politics, has surged back into discussion amid a widening wealth gap and the rise of avowedly social-democratic politicians such as Bernie Sanders and Alexandria Ocasio-Cortez in the U.S. While the inequality motif is poised to rally New Democrats around a common theme this …