Checkpoint source 7 workflows and in-progress diagram authoring redesign

Preserve current core, source, REST, desktop, recovery, documentation and validation work, including AGENTS.md and the development summary. This is a work-in-progress checkpoint: the new compact palette has outstanding compilation errors and native acceptance; earlier passing gates retain their documented scope.

crates/oa-core/src/view_options.rs

@@ -1,7 +1,10 @@
 //! Persisted view intent and pure visibility decisions over actual model identities.
 //! Build `ViewIndex` once per accepted model revision. Preparing a view performs
 //! set unions/reachability once; testing an edge never walks the model.
-use crate::{Id, Kind, Layer, OccurrenceBody, Project, RelationKind, SharedBody};
+use crate::{
+    ContextualLinkPurpose, Id, Kind, Layer, OccurrenceBody, Project, RelationBody, RelationKind,
+    SharedBody,
+};
 use serde::{Deserialize, Serialize};
 use std::collections::{BTreeMap, BTreeSet};
 
@@ -401,6 +404,25 @@ impl BehaviorIndex {
                 _ => {}
             }
         }
+        let topology = crate::topology_context::TopologyIndex::new(p);
+        for relation in p.relations.values() {
+            if let RelationBody::ContextualLink {
+                owner,
+                source,
+                target,
+                purpose: purpose @ ContextualLinkPurpose::Exchange { exchange },
+            } = &relation.body
+                && topology
+                    .validate_link(*owner, source, target, purpose)
+                    .is_ok()
+            {
+                let facts = index.facts.entry(*owner).or_default();
+                facts.exchanges.insert(*exchange);
+                if let Some(exchange) = p.relations.get(exchange) {
+                    facts.work.extend([exchange.source(), exchange.target()]);
+                }
+            }
+        }
         index
     }