Admit E3 and capacity on the test plane

Register in-process E3 and capacity fixtures, keep live database and
substrate targets pending, and ask ops-mason for namespace-only provision.
No packets, no credentials, no cancelled engagement IDs.

Assistant: grok
Assistant-Session: 01a02670-3345-76f2-a014-70fde8e2a2bb

targets/shared-substrate-capacity.json

@@ -0,0 +1,21 @@
+{
+  "schema_version": "whitehat-target/v1",
+  "target_id": "shared-substrate",
+  "posture_claim": "P1/P2",
+  "attacker_model": "bounded co-resident saturating its own allowance",
+  "applicability": "pending",
+  "applicability_reason": "No operator-approved substrate window or aggressor ceiling exists. Saturation against a shared rail is an outage if run without those bounds. This registration does not authorize load.",
+  "approval_classes": ["capacity"],
+  "routes": [],
+  "identities": {
+    "count": 0,
+    "role": "none until a window names the aggressor consumer",
+    "broker_audience": "whitehat-capacity/shared-substrate"
+  },
+  "abort_telemetry": [
+    "governor_unbound",
+    "aggressor_exceeded_ceiling",
+    "missing_neighbour_sample",
+    "shared_substrate_abort_threshold"
+  ]
+}