Complete service-account credential administration

README.md

@@ -76,7 +76,7 @@ adds tenant administration plus tenant resolver behavior when installed.
 ## Principal Context
 
 The stable principal DTO is `govoplan_core.core.access.PrincipalRef`. Access
-resolves sessions, API keys, and future service accounts into that DTO and
+resolves sessions, API keys, and service-account credentials into that DTO and
 serializes it as `principal` in auth API responses. Feature modules should use
 that DTO, primitive IDs, or the core `govoplan_core.auth` dependency facade
 instead of importing access ORM models or backend dependency internals.
@@ -95,6 +95,15 @@ current roles, groups, functions, and delegations and intersects that
 authorization with the stored grant. Missing, inactive, moved, or
 under-authorized owners fail closed before module work starts.
 
+Tenant administrators manage non-login service accounts under
+`Admin > Tenant > Service accounts`. Each service account has a revisioned
+scope ceiling and independently revocable API credentials. Credential secrets
+are shown once; runtime authorization intersects the credential grant with the
+current ceiling. Rotation creates a replacement and revokes the previous
+credential atomically, while retirement revokes every active credential. See
+[docs/SERVICE_ACCOUNTS.md](docs/SERVICE_ACCOUNTS.md) for the API and operational
+contract.
+
 ## WebUI Package
 
 The repository root and `webui/` directory both expose the package