Build multinode test policies in the inputs shape so they reference their sources

testing/compose/multinode/seed.sh

@@ -146,10 +146,12 @@ JSON
   fi
 
   if [ -n "${src_id:-}" ]; then
+    # 'inputs', not the legacy {trigger, sourceIds}: Policy has no sourceIds field, so the old
+    # shape binds inputs=null and seeds a policy that watches nothing while still returning 200.
     pol_body=$(cat <<JSON
 {"name":"Compress incoming PDFs","enabled":true,
- "trigger":{"type":"schedule","options":{"schedule":{"type":"every","count":5,"unit":"MINUTES"}}},
- "sourceIds":["$src_id"],
+ "inputs":[{"sourceId":"$src_id",
+            "trigger":{"type":"schedule","options":{"schedule":{"type":"every","count":5,"unit":"MINUTES"}}}}],
  "steps":[{"operation":"/api/v1/misc/compress-pdf","parameters":{}}],
  "output":{"type":"s3","options":{"connectionId":$conn_id,"prefix":"processed/"}}}
 JSON

testing/cucumber/features/steps/multinode_step_definitions.py

@@ -101,9 +101,11 @@ def _names_on_node(node, path, token):
 
 
 def _policy_body(name, source_ids=None, enabled=True):
+    # Must be the 'inputs' shape. Policy has no sourceIds field, so a legacy
+    # {sourceIds, trigger} body binds inputs=null and silently stores a policy referencing nothing.
     return json.dumps({
-        "name": name, "enabled": enabled, "trigger": None,
-        "sourceIds": source_ids or [],
+        "name": name, "enabled": enabled,
+        "inputs": [{"sourceId": sid, "trigger": None} for sid in (source_ids or [])],
         "steps": [{"operation": "/api/v1/misc/compress-pdf", "parameters": {}}],
         "output": {"type": "inline", "options": {}},
     })