Count how many jobs match a search without returning full results. Returns structured JSON.

Use this when the user asks "how many jobs..." (in any language), including salary-constrained counts like "how many jobs pay at least 60k?" or "how many jobs advertise a salary at all?" (use has_salary=True).

Args: q: Search keywords, e.g. "Softwareentwickler Python" location: City or region, e.g. "München", "Bodensee" working_plan: "Vollzeit", "Teilzeit", "Homeoffice", or "Minijob" job_offer_type: "Arbeitsplatz", "Ausbildung", "Praktikum", "Freiberuflich", "Werkstudent", "Trainee", "Duales-Studium" min_salary: Minimum ANNUAL gross salary in EUR (optional), e.g. 60000. Filtered server-side with the same semantics as search_jobs: monthly/hourly amounts are normalised to a yearly figure first, and salary ranges match on overlap. A job with range 30.000–45.000 € is counted at min_salary=40000 (ranges overlap). max_salary: Maximum annual gross salary in EUR (optional, same semantics). A job with range 30.000–45.000 € is NOT counted at max_salary=25000. has_salary: If True, count only jobs that advertise a salary at all (regardless of amount). If False, count only jobs WITHOUT a salary. Leave unset to ignore. Use this for "how many jobs have a salary?"; combine with min_salary/max_salary as needed.

Returns: On success: {"count": int, "filters": {"q": str|null, "location": str|null, "working_plan": str|null, "job_offer_type": str|null, "min_salary": float|null, "max_salary": float|null, "has_salary": bool|null}} On error: {"error": str}