Api Learning Daily Practice Complete

Submit a completed daily-practice session.

Body: {answers: [{module_id: str, chosen_index: int, category: str}]}

#96 (2026-08-13): this line used to read {questions_answered: int, correct_count: int}. It is the endpoint's PUBLIC OpenAPI description, so leaving it would have advertised a body the handler now refuses — the api-docs equivalent of the defect being fixed. Sessions are graded SERVER-SIDE against the answer key; a caller supplies only what it chose.

Updates user_daily_practice_log (questions answered today) and bumps user_daily_streaks (+1 if today is day-after-last-practice, reset to 1 if there was a gap). Returns the new streak values + the refreshed 7-day ring.