chore(pchome): track auto policy receipt migration

migrations/045_pchome_auto_policy_evidence_receipts.sql

@@ -0,0 +1,31 @@
+-- =============================================================================
+-- Migration 045: PChome auto-policy evidence receipts
+-- MOMO PRO / PChome revenue growth automation
+-- 2026-06-28 Taipei
+-- =============================================================================
+-- Notes:
+--   Additive only. This migration creates a receipt ledger for controlled
+--   PChome evidence persistence. It does not drop, truncate, rewrite, or
+--   backfill external_offers / competitor_* / product sales tables.
+-- =============================================================================
+
+CREATE TABLE IF NOT EXISTS external_offer_evidence_receipts (
+    receipt_id TEXT PRIMARY KEY,
+    pchome_product_id TEXT NOT NULL,
+    automation_decision TEXT NOT NULL,
+    payload_hash TEXT NOT NULL,
+    evidence_delta_json JSONB NOT NULL DEFAULT '{}'::jsonb,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
+    applied_at TIMESTAMPTZ,
+    apply_status TEXT NOT NULL DEFAULT 'previewed'
+);
+CREATE INDEX IF NOT EXISTS idx_external_offer_evidence_receipts_pchome_product_id ON external_offer_evidence_receipts (pchome_product_id);
+CREATE INDEX IF NOT EXISTS idx_external_offer_evidence_receipts_payload_hash ON external_offer_evidence_receipts (payload_hash);
+CREATE INDEX IF NOT EXISTS idx_external_offer_evidence_receipts_apply_status ON external_offer_evidence_receipts (apply_status);
+
+GRANT ALL PRIVILEGES ON external_offer_evidence_receipts TO momo;
+
+DO $$
+BEGIN
+    RAISE NOTICE 'Migration 045 complete: PChome auto-policy evidence receipts are ready';
+END $$;