Get Outreach Contacts

List contacts (people emailed in this segment) with send + reply status.

Paged: returns {contacts, has_more, next_offset, total_count}. Optional filters:

• search: receiver or sender email (case-insensitive substring).
• intent: comma-separated intent names (e.g. "hot_lead,not_interested") — drives the inbox filter pills and dashboard deep-links. Unknown values silently degrade to no-filter.
• ab: repeatable A/B cohort filter "<exp_id>:<arm>". When present, only contacts whose agent_lead.ab_arms row carries every requested (exp, arm) pair are returned. Validated against the lead-level REGISTRY in api/outreach/experiments.py; unknown ids / invalid arms degrade to no-filter. Used by team/QA to slice the inbox by experiment cohort via the API — no UI surface. Examples: ?ab=followup_v1:fresh_subject, ?ab=followup_v1:control&ab=email_model_v1:mini.