Get model AI agent actions

Return AI agent actions configured for a model — a unified list of sample queries and skills suitable for surfacing as suggested prompts in AI interfaces.

Sample queries come from both model.sample_queries and each topic's sample_queries. Skills come from model.skills and each topic's skills, deduped by ID with topic skills overriding model skills.

When no actions are configured at the model or topic level, records returns an empty array.