Summarize Python Sales Records

At Acme Analytics, raw sales events are represented as Python dictionaries. Write a function that groups valid records by category, sums revenue per category, and returns the top k categories.

A record is valid only if it contains the keys category, price, and quantity, where category is a non-empty string and both price and quantity are non-negative numbers. Revenue for one record is price * quantity. If multiple valid records share the same category, their revenues should be added together. Return the result as a list of [category, total_revenue] pairs sorted by descending total revenue; if two categories have the same revenue, sort them by ascending category name. Return only the first k pairs. If k is larger than the number of categories, return all categories.