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-desktop/src/semantic_review/constructor_tests.rs

@@ -463,6 +463,7 @@ fn occurrence_and_event_candidate_variants_cover_closed_families_without_touchin
             lifeline: None,
         },
         OccurrenceBody::Exchange {
+            operation: None,
             exchange: None,
             sender: None,
             receiver: None,
@@ -519,6 +520,7 @@ fn occurrence_and_event_candidate_variants_cover_closed_families_without_touchin
                     body: OccurrenceBody::Action { .. },
                     ..
                 } => occurrence(OccurrenceBody::Exchange {
+                    operation: None,
                     exchange: None,
                     sender: None,
                     receiver: None,
@@ -725,6 +727,7 @@ fn port_group_companions_typed_owner_context_and_direction_restrictions_are_expl
 #[test]
 fn outer_and_nested_constructor_candidates_require_explicit_resolution_and_retain_both_drafts() {
     let original = occurrence(OccurrenceBody::Exchange {
+        operation: None,
         exchange: None,
         sender: None,
         receiver: None,
@@ -1319,6 +1322,7 @@ fn closed_data_and_event_take_composition_matches_core_across_every_kind_pair_an
 fn exchange_constructor_takes_qualified_annotation_addresses_without_remapping_expression_text() {
     for reverse in [false, true] {
         let message = occurrence(OccurrenceBody::Exchange {
+            operation: None,
             exchange: None,
             sender: None,
             receiver: None,