Add Keto service + migrate (todo §3); OPL role/group/resource namespaces, fine-grained resource permits

ory/keto/namespaces.keto.ts

@@ -0,0 +1,47 @@
+// Ory Permission Language (OPL) — the authorization model Keto enforces. Keto parses
+// this file (referenced by keto.yml `namespaces.location`); the `@ory/keto-namespace-types`
+// import is for the author's editor only and is ignored at load. Subject ids are Kratos
+// identity ids (== the JWT `sub`).
+import { Context, Namespace, SubjectSet } from "@ory/keto-namespace-types"
+
+// A human identity. Subjects are written as `user:<kratos-identity-id>`.
+class User implements Namespace {}
+
+// A subject set: a named collection of users (and nested groups), resolved transitively.
+// The admin "Groups" screen (§5) manages membership; checks expand it automatically.
+class Group implements Namespace {
+  related: {
+    members: (User | SubjectSet<Group, "members">)[]
+  }
+}
+
+// A coarse role — the source of truth for the JWT `roles` claim. At login the app reads
+// `role:<name>#members@user:<id>` from Keto and projects the result into the token
+// (README: Login → session JWT). A group can hold a role, so members can be users or groups.
+class Role implements Namespace {
+  related: {
+    members: (User | SubjectSet<Group, "members">)[]
+  }
+}
+
+// A fine-grained, relationship-checked resource — README's third "may I?" tier, the rare
+// live Keto check (e.g. sharing/delegation). Permissions nest: owner ⊇ editor ⊇ viewer.
+// Grants accept a user directly or any member of a group.
+class Resource implements Namespace {
+  related: {
+    owners: (User | SubjectSet<Group, "members">)[]
+    editors: (User | SubjectSet<Group, "members">)[]
+    viewers: (User | SubjectSet<Group, "members">)[]
+  }
+
+  permits = {
+    view: (ctx: Context): boolean =>
+      this.related.viewers.includes(ctx.subject) ||
+      this.related.editors.includes(ctx.subject) ||
+      this.related.owners.includes(ctx.subject),
+    edit: (ctx: Context): boolean =>
+      this.related.editors.includes(ctx.subject) ||
+      this.related.owners.includes(ctx.subject),
+    delete: (ctx: Context): boolean => this.related.owners.includes(ctx.subject),
+  }
+}