add reversible prospect deduplication

apps/api/schema.sql

@@ -25,6 +25,14 @@ CREATE TABLE IF NOT EXISTS businesses (
  score_version TEXT NOT NULL DEFAULT 'mvp-1', score_factors TEXT NOT NULL DEFAULT '[]', website_class TEXT NOT NULL DEFAULT 'missing',
  verified INTEGER NOT NULL DEFAULT 0, verified_at TEXT, created_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP, updated_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP
 );
+-- Phase 6 normalized location and reversible merge ledger.
+CREATE TABLE IF NOT EXISTS merge_history (
+ id INTEGER PRIMARY KEY AUTOINCREMENT, organization_id TEXT NOT NULL REFERENCES organizations(id),
+ source_business_id INTEGER NOT NULL REFERENCES businesses(id), target_business_id INTEGER NOT NULL REFERENCES businesses(id),
+ source_snapshot_json TEXT NOT NULL, child_reassignment_json TEXT NOT NULL DEFAULT '{}', actor_user_id INTEGER REFERENCES users(id) ON DELETE SET NULL,
+ reversible INTEGER NOT NULL DEFAULT 1, reversed_at TEXT, created_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP
+);
+CREATE INDEX IF NOT EXISTS idx_merge_history_org ON merge_history(organization_id,created_at DESC,id DESC);
 CREATE INDEX IF NOT EXISTS idx_businesses_org ON businesses(organization_id);
 CREATE INDEX IF NOT EXISTS idx_businesses_score ON businesses(organization_id,score DESC,id);
 CREATE INDEX IF NOT EXISTS idx_businesses_class ON businesses(organization_id,website_class);