test(infra): verify-objecten asserts Objecten API up + token auth + trusts Objecttypen (refs #140)

Fails against the current stack (no objecten service yet) with a clear
"no running objecten container" message. Green comes with the compose
service + seeded setup_configuration in the next commit.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

infra/objecten-check.py

@@ -0,0 +1,49 @@
+#!/usr/bin/env python3
+"""S-18b (#140): prove the Objecten API is up and its static token authenticates.
+
+Assert an unauthenticated call to /api/v2/objects is 401 and an authenticated one (the seeded dev
+token) is 200 — i.e. the service migrated, booted, and setup_configuration provisioned the token
+and the Objecttypen service it trusts. Stdlib only so it runs in a bare python:3-slim container on
+the compose network.
+"""
+import os
+import sys
+import time
+import urllib.error
+import urllib.request
+
+BASE = os.environ["OBJECTEN"]          # http://<ip>:8000
+TOKEN = os.environ["OBJECTEN_TOKEN"]
+TIMEOUT = int(os.environ.get("OBJECTEN_TIMEOUT", "60"))
+
+
+def status(url, token=None):
+    req = urllib.request.Request(url)
+    if token:
+        req.add_header("Authorization", f"Token {token}")
+    try:
+        with urllib.request.urlopen(req, timeout=10) as r:
+            return r.status
+    except urllib.error.HTTPError as e:
+        return e.code
+    except Exception:
+        return 0
+
+
+def main():
+    url = f"{BASE}/api/v2/objects"
+    deadline = time.time() + TIMEOUT
+    while time.time() < deadline:
+        unauth = status(url)
+        authed = status(url, TOKEN)
+        if unauth == 401 and authed == 200:
+            print(f"OK — {url}: no-auth {unauth}, token {authed}")
+            return 0
+        time.sleep(3)
+    print(f"FAIL — {url}: expected no-auth 401 + token 200, got {status(url)} / {status(url, TOKEN)}",
+          file=sys.stderr)
+    return 1
+
+
+if __name__ == "__main__":
+    sys.exit(main())