docs: integrate approved Next Go architecture

.project-docs/20-architecture/module-map.md

@@ -16,6 +16,22 @@
 - Routes and services depend on store interfaces; stores depend on the shared database adapter; the adapter does not depend on domain stores.
 - Worker depends on the internal Web HTTP API, not the database module.
 
+## Approved Target Module Map
+
+The target below is a design contract, not current source layout:
+
+| Target Module | Interface | Implementation notes |
+|---|---|---|
+| Next.js frontend | Pages, SSR, and same-origin browser calls | Forwards Cookie/request context to Go; no direct persistence or domain ownership. |
+| Go Identity | Login/logout/session/password/authorization | Preserves the current signed chunked Cookie and per-request account/organization/sessionVersion validation. |
+| Go Administration | Organizations, accounts, settings visibility, logs, administrative usage | Enforces current super-admin and organization-admin rules. |
+| Go Assets | Register/upload/list/get/delete/download | Uses object-storage Adapter; preserves owner-scoped 404 and storage metadata. |
+| Go Jobs | Submit/query/cancel/retry/claim/execute/terminal transitions/Webhooks | Uses the PostgreSQL claim function and hides provider/retry/refund state. |
+| Go Billing | Quote/wallet/ledger/price/charge/refund/settlement | Uses the PostgreSQL wallet function and integer-fen arithmetic. |
+| Go Usage | Platform/public attribution and usage records | Retains organization/account context and job uniqueness. |
+
+Real internal seams are PostgreSQL transport, object storage, generation providers, and deterministic test dependencies. Avoid one shallow repository Interface per table.
+
 ## Risky Or Sensitive Areas
 
 - `database/migrations/` and the two concurrency-sensitive PostgreSQL functions.