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/tests/language.rs

@@ -363,6 +363,49 @@ project mission "Harbor safety — 港 🌊" {
         family: oa_core::view_options::ExchangeFamily::Participant,
         exchanges: vec![means],
     };
+    let caller = p
+        .add_element(Kind::Process, Layer::Oa, "Common work caller", None)
+        .unwrap();
+    let work = p
+        .elements
+        .values()
+        .find(|e| e.kind() == Kind::Activity)
+        .unwrap()
+        .id;
+    let mut occurrences = vec![];
+    for name in ["First contribution", "Second contribution"] {
+        let id = p
+            .add_element(Kind::Occurrence, Layer::Oa, name, Some(caller))
+            .unwrap();
+        *p.elements.get_mut(&id).unwrap().shared_mut().unwrap() = SharedBody::Occurrence {
+            body: OccurrenceBody::Action {
+                action: Some(work),
+                lifeline: None,
+            },
+            precondition: String::new(),
+            postcondition: String::new(),
+        };
+        occurrences.push(id);
+    }
+    *p.elements.get_mut(&caller).unwrap().steps_mut().unwrap() = occurrences.clone();
+    let id = p.relate(
+        RelationKind::ContextualLink,
+        "Shared work incidence",
+        occurrences[0],
+        occurrences[1],
+    );
+    p.relations.get_mut(&id).unwrap().body = RelationBody::ContextualLink {
+        owner: caller,
+        source: OccurrenceEndpoint {
+            references: vec![],
+            occurrence: occurrences[0],
+        },
+        target: OccurrenceEndpoint {
+            references: vec![],
+            occurrence: occurrences[1],
+        },
+        purpose: ContextualLinkPurpose::CommonWork { work },
+    };
     p
 }
 
@@ -515,7 +558,7 @@ fn authoring_defaults_and_forward_references_remain_strict() {
 #[test]
 fn typed_unknown_fields_enums_duplicates_and_reference_spelling_are_rejected() {
     for (source, expected) in [
-        ("arcadia 7; project mission \"x\" {}", "Unsupported schema"),
+        ("arcadia 8; project mission \"x\" {}", "Unsupported schema"),
         (
             "arcadia 2; project mission \"x\" { oa_activity a \"A\" { nonsense 1; } }",
             "Unknown field",
@@ -1219,11 +1262,10 @@ fn complete_normative_examples_are_accepted_by_the_real_parser() {
                 break;
             }
         }
-        if code.trim_start().starts_with("arcadia 2;")
-            || code.trim_start().starts_with("arcadia 3;")
-            || code.trim_start().starts_with("arcadia 4;")
-            || code.trim_start().starts_with("arcadia 6;")
-        {
+        if (1..=SCHEMA_VERSION).any(|version| {
+            code.trim_start()
+                .starts_with(&format!("arcadia {version};"))
+        }) {
             read(&code);
             examples += 1;
         }