THE financially troubled Oakland Tribune has received a one-day reprieve in its effort to resolve a $31 million debt owed to its former owner, media giant Gannett Company, the newspaper's publisher said.Owner Robert Maynard said in a statement that the Tribune, which had been expected to publish its final edition Wednesday, would be printed Thursday. A Gannett official at the company's headquarters in Arlington, Va., had no comment. Maynard announced last Thursday that the paper would publish its final edition Wednesday if the debt could not be restructured. He said his offer of $2.5 million in payment for the debt was turned down by Gannett last week, jeopardizing a tentative agreement with an unnamed investor who was willing to rescue the 117-year-old newspaper. If the Tribune folds, Oakland, a city of 350,000, would become the nation's largest city without a daily newspaper. Maynard and his wife, Nancy, bought the Tribune in 1983, making it the only daily newspaper in the nation published by a black family.