fix(words): Relations-Setup automatisch beim ersten Word-Save

words_pictures M2M-Relationen werden idempotent beim POST eingerichtet –
kein manueller Setup-Call nötig.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app.py

@@ -149,7 +149,36 @@ def directus_picture_words(pic_id):
     else:  # POST
         body = request.get_json(force=True, silent=True) or {}
         words = body.get("words", [])
+
+        # Junction + Relationen idempotent einrichten
         _ensure_junction("words_pictures", "words_id", "pictures_id", token)
+        _directus("PATCH", "/fields/pictures/linked_words", token, {
+            "type": "alias",
+            "meta": {"special": ["m2m"], "interface": "list-m2m",
+                     "options": {"template": "{{words_id.title_de}}"}},
+        })
+        _directus("PATCH", "/fields/words/linked_pictures", token, {
+            "type": "alias",
+            "meta": {"special": ["m2m"], "interface": "list-m2m",
+                     "options": {"template": "{{pictures_id.media}}"}},
+        })
+        _directus("POST", "/relations", token, {
+            "collection": "words_pictures", "field": "words_id",
+            "related_collection": "words",
+            "schema": {"on_delete": "CASCADE"},
+            "meta": {"junction_field": "pictures_id",
+                     "one_field": "linked_pictures",
+                     "one_deselect_action": "nullify"},
+        })
+        _directus("POST", "/relations", token, {
+            "collection": "words_pictures", "field": "pictures_id",
+            "related_collection": "pictures",
+            "schema": {"on_delete": "CASCADE"},
+            "meta": {"junction_field": "words_id",
+                     "one_field": "linked_words",
+                     "one_deselect_action": "nullify"},
+        })
+
         saved = 0
         for entry in words:
             title_de = (entry.get("title_de") or "").strip()