Add state diagram form and representation contract parity

docs/openapi.json

@@ -3685,6 +3685,53 @@
         ],
         "additionalProperties": false
       },
+      "ProjectionKind": {
+        "description": "Existing projections remain strings. StateMachine carries one required UUID reference to an existing StateMachine in the diagram layer (state_diagram_context). Its placements may contain only that machine and its regions/state vertices, including nested members (state_diagram_member). Empty and partial views are valid. Incompatible placements must be removed or relocated in the same transaction when changing context; accepting or reading a view does not synthesize semantic records or placements.",
+        "oneOf": [
+          {
+            "type": "string",
+            "enum": [
+              "FunctionalDataflow",
+              "Capabilities",
+              "Overview",
+              "Decomposition",
+              "Allocation",
+              "Traceability"
+            ]
+          },
+          {
+            "type": "object",
+            "properties": {
+              "StateMachine": {
+                "type": "object",
+                "properties": {
+                  "machine": {
+                    "type": "string",
+                    "format": "uuid",
+                    "description": "Required identity of the same-layer StateMachine that owns this view's members."
+                  }
+                },
+                "required": [
+                  "machine"
+                ],
+                "additionalProperties": false
+              }
+            },
+            "required": [
+              "StateMachine"
+            ],
+            "additionalProperties": false
+          }
+        ],
+        "examples": [
+          "Overview",
+          {
+            "StateMachine": {
+              "machine": "11111111-1111-4111-8111-111111111111"
+            }
+          }
+        ]
+      },
       "Diagram": {
         "type": "object",
         "properties": {
@@ -3707,15 +3754,7 @@
             "$ref": "#/components/schemas/Layer"
           },
           "projection": {
-            "type": "string",
-            "enum": [
-              "FunctionalDataflow",
-              "Capabilities",
-              "Overview",
-              "Decomposition",
-              "Allocation",
-              "Traceability"
-            ]
+            "$ref": "#/components/schemas/ProjectionKind"
           },
           "nodes": {
             "type": "object",