Byol Import Leads

Bring-your-own-leads (T-44): import a self-contained CSV into a new created_by='import' campaign — leads inserted directly from the provided fields (never gated on our CH base), enriched from our base where possible, emails verified (free), deduped, then AUTO-APPROVED into outreach.

Streams NDJSON progress events so the import screen shows live progress instead of a frozen spinner (verification is the slow step): {"type":"progress","stage":"verifying","done":42,"total":100} then a terminal {"type":"result", ...} or {"type":"error","detail":...}.

Feature flag: the UI entry is gated by byol_import (default off, toggled on /feature-flags). The flag is the rollout control; this endpoint just requires an authenticated org member.