Billing docs improvement + build opt

README.md

@@ -25,14 +25,15 @@ Financial services platform providing payment orchestration, ledger accounting,
 | Gateway Chain | `api/gateway/chain/` | EVM blockchain gateway |
 | Gateway TRON | `api/gateway/tron/` | TRON blockchain gateway |
 | Gateway Aurora | `api/gateway/aurora/` | Card payouts simulator |
+| Gateway ChimeraSettle | `api/gateway/chsettle/` | Dummy settlement simulator (fast/slow/success/fail/stuck) |
 | Gateway MNTX | `api/gateway/mntx/` | Card payouts |
-| Gateway TGSettle | `api/gateway/tgsettle/` | Telegram settlements with MNTX |
+| Gateway TGSettle (legacy) | `api/gateway/tgsettle/` | Legacy Telegram settlement gateway (not used in dev compose) |
 | Notification | `api/notification/` | Notifications |
 | BFF | `api/edge/bff/` | Backend for frontend |
 | Callbacks | `api/edge/callbacks/` | Webhook callbacks delivery |
 | Frontend | `frontend/pweb/` | Flutter web UI |
 
-Gateway note: current dev compose workflows (`make services-up`, `make build-gateways`) use Aurora for card-payout flows (`chain`, `tron`, `aurora`, `tgsettle`). The MNTX gateway codebase is retained separately for Monetix-specific integration.
+Gateway note: current dev compose workflows (`make services-up`, `make build-gateways`) use (`chain`, `tron`, `aurora`, `chsettle`). ChimeraSettle is the settlement simulator for test flows; it supports deterministic behavior routing via explicit scenario override and amount buckets. TGSettle remains in-repo as legacy code and is not started by default in dev compose.
 
 ## Prerequisites
 
@@ -87,7 +88,7 @@ make list-services # Show service names, ports, and descriptions
 make build-core       # discovery, ledger, fees, documents
 make build-fx         # oracle, ingestor
 make build-payments   # orchestrator, quotation, methods
-make build-gateways   # chain, tron, aurora, tgsettle
+make build-gateways   # chain, tron, aurora, chsettle
 make build-api        # notification, callbacks, bff
 make build-frontend   # Flutter web UI
 ```