Mike Bloomberg will join the Democratic presidential debate stage for the first time Wednesday night, but he’s already been a fixture in Colorado living rooms for months, as he’s flooded the airwaves with more than $5 million in TV ads. Go back further, and the billionaire former New York City mayor has showered Colorado in cash for much of the last decade — long before he was a candidate. Bloomberg and associated organizations have sent well in excess of $10 million to the state in the form of charitable contributions, local government grants and, most prominently, political donations that helped fuel Colorado’s debates on guns and education reforms, according to a Denver Post analysis of campaign finance records and media reports. Bloomberg’s past activity bought him a reserve of goodwill in Colorado that he’s drawing on now as he builds the biggest state campaign staff of the major Democratic candidates.