Built-in OAuth2 client-registration admin screen (todo §6); /admin/clients lists/registers/deletes the Hydra OAuth2 clients other apps log in through us with. New src/admin-clients.ts (pure builders + handleAdminClients, mirroring the §5 Users/Roles screens): list (search/paginate over one fetched Hydra page), register (GET form + POST), read-only detail, delete-confirm. src/hydra-admin.ts gains the client half of the admin API — createClient/listClients/getClient/deleteClient over /admin/clients (+ a nextPageToken Link parser like kratos-admin) and the registration fields on OAuth2Client. Register builds a standard authorization-code client (+ refresh_token), confidential (client_secret_basic) or public (PKCE/none), with an optional first-party auto-consent flag; Hydra returns the client_secret once, so the register POST renders the new client's detail page with the one-time secret directly (no PRG) and it is never re-shown (getClient carries no secret; the detail test asserts it). Writes go only to Hydra; gated admin-only (anon->/login, non-admin->403) + every mutation CSRF-guarded via requireAdmin/guardedForm like §5; a Hydra 4xx (bad redirect/scope) re-renders the form (400), a 5xx -> 500 (mirrors oauth-login.ts); :id via safeDecode (malformed->404). Wired into app.ts (/admin/clients, gated on the hydra client present) and the shared adminSection (Users.Groups.Roles.OAuth2 clients, i-globe) so it shows for admins and is invisible otherwise. New views (admin/clients, client-form, client-detail + partials/client-{form,detail}-body) reuse the shell/filter-bar/data-table/field blocks; one .detail-list CSS rule; README Layout/§6 updated. Tests-first: hydra-admin.test.ts (client CRUD contracts incl. Link pagination/404->null/204), admin-clients.test.ts (builder/validation/payload matrix), app.test.ts HTTP integration (gate/list/register-shows-secret-once/invalid+CSRF-reject/detail-hides-secret/delete + malformed-%->404). Stability-reviewer run as a local PR: APPROVE, no Critical/High; addressed its one nit (dropped a dead URL.protocol check in validateClientInput). Boot-verified the client CRUD live against real Hydra v26.2.0 (create->201 w/ one-time secret -> list finds it -> get -> delete -> get null); torn down. typecheck + 274 units green.

public/css/styles.css

@@ -678,6 +678,9 @@ th[aria-sort="descending"] .sort-ico { transform: rotate(180deg); }
 .admin-actions { flex-flow: row wrap; gap: 10px; align-items: center; }
 .admin-actions form { margin: 0; }
 .plain-list { display: flex; flex-direction: column; gap: 6px; }
+.detail-list { display: grid; grid-template-columns: max-content 1fr; gap: 6px 18px; margin: 0; font-size: var(--fz-sm); }
+.detail-list dt { color: var(--text-faint); }
+.detail-list dd { margin: 0; word-break: break-word; }
 .btn-danger { color: var(--neg); border-color: var(--neg-bd); }
 .btn-danger:hover { background: var(--neg-bg); }
 .recovery-link { word-break: break-all; }