Compose saved Scenario authoring with current Text and input authority

crates/oa-core/src/model.rs

@@ -1436,6 +1436,7 @@ pub enum ProjectionKind {
     FunctionalDataflow,
     Capabilities,
     StateMachine { machine: Id },
+    Scenario { scenario: Id },
 }
 impl ProjectionKind {
     pub fn state_machine(self) -> Option<Id> {
@@ -1445,8 +1446,30 @@ impl ProjectionKind {
         }
     }
 
+    /// The semantic owner of a saved Scenario representation.
+    pub fn scenario(self) -> Option<Id> {
+        match self {
+            Self::Scenario { scenario } => Some(scenario),
+            _ => None,
+        }
+    }
+
+    /// Explicitly classify architecture views; absence of a state machine is insufficient.
+    pub fn is_architecture(self) -> bool {
+        match self {
+            Self::Overview
+            | Self::Decomposition
+            | Self::Allocation
+            | Self::Traceability
+            | Self::FunctionalDataflow
+            | Self::Capabilities => true,
+            Self::StateMachine { .. } | Self::Scenario { .. } => false,
+        }
+    }
+
     pub fn includes(self, kind: Kind) -> bool {
         match self {
+            Self::Scenario { .. } => false,
             Self::StateMachine { .. } => {
                 matches!(kind, Kind::StateMachine | Kind::Region) || kind.is_state()
             }
@@ -1471,6 +1494,7 @@ impl std::fmt::Display for ProjectionKind {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         f.write_str(match self {
             Self::StateMachine { .. } => "State machine",
+            Self::Scenario { .. } => "Scenario",
             Self::Allocation => "Architecture · allocated work",
             Self::FunctionalDataflow => "Functional dataflow",
             Self::Capabilities => "Missions & capabilities",
@@ -1495,6 +1519,8 @@ pub struct Diagram {
     pub nodes: BTreeMap<Id, NodePlacement>,
     #[serde(default)]
     pub routes: Vec<EdgeRoute>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub layout: Option<crate::scenario_layout::DiagramLayout>,
 }
 /// Authored presentation for one existing relation or trace in one diagram.
 /// Computed endpoints and automatic routing elbows are never persisted here.
@@ -1921,6 +1947,7 @@ impl Project {
                 view_options: crate::view_options::ViewOptions::default(),
                 nodes: BTreeMap::new(),
                 routes: vec![],
+                layout: None,
             },
         );
         id