keycloak: provide oidc-client, one mesh-made client per consumer

A module that logs people in through Keycloak had to be given a client by
hand, with its secret copied into the consumer's environment. As a provision
the mesh derives the client id (the consumer's identity, mesh_<node>_<module>)
and mints its secret, and delivers both ends: keycloak creates exactly that
confidential client, the consumer names it through ${bound:oidc-client:as}.

The consumer says where its browser comes back to (`callback`) and which
endpoint it is reached on (`label`/`endpoint`), so the redirect is built from
the same names the mesh composes for its route. keycloak serves the issuer and
the endpoint paths under it; the issuer is the one value an assignment sets,
and the realm is read out of it, so consumer and client cannot disagree.

Only what the mesh made is touched: its clients carry mesh.provisioned=true;
a client of the same id without the mark is refused, never adopted, updated
or deleted. The runtime now gets the admin password as a file, which its
tools also needed and never had.

modules/keycloak/package.json

@@ -1,11 +1,15 @@
 {
   "name": "@novox/module-keycloak",
   "version": "0.1.0",
-  "description": "keycloak — identity and access. Its admin API client, tools and events live here (novox/hq ADR 0039).",
+  "description": "keycloak — identity and access; provides the mesh oidc-client interface. Its admin API client, provisioner, tools and events live here (novox/hq ADR 0039).",
   "type": "module",
   "private": true,
+  "scripts": {
+    "build": "tsc client.ts oidc.ts index.ts provisioner/index.ts tools/index.ts --module NodeNext --moduleResolution NodeNext --target ES2022 --outDir dist",
+    "test": "npm run build && node --test --experimental-strip-types 'test/*.test.ts'"
+  },
   "dependencies": {
-    "@novox/mesh-sdk": "^0.1.0"
+    "@novox/mesh-sdk": "^0.1.1"
   },
   "devDependencies": {
     "@types/node": "^22.0.0",