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-server/tests/http.rs

@@ -18,6 +18,8 @@ mod port_anchors;
 mod semantic_transitions;
 #[path = "http/source6_views.rs"]
 mod source6_views;
+#[path = "http/source7_contracts.rs"]
+mod source7_contracts;
 #[path = "http/source_projects.rs"]
 mod source_projects;
 
@@ -567,89 +569,6 @@ async fn oversized_source_and_json_are_rejected_without_stalling_the_catalog() {
     server.stop().await;
 }
 
-#[tokio::test]
-async fn accepted_slow_source_does_not_lock_catalog_and_loses_to_a_newer_http_revision() {
-    let directory = tempfile::tempdir().unwrap();
-    let server = TestServer::start(directory.path(), None).await;
-    let (id, etag) = server.create().await;
-    let mut source = String::from(
-        "arcadia 2; project prepared \"Slow proposed head\" { oa_activity a0 \"Root\" {}\n",
-    );
-    // This is within all admission budgets. A nested engineering graph forces
-    // real validation work after the source route's initial revision snapshot.
-    // Keep this concurrency fixture below the service's 30-second deadline:
-    // 2,000 nested activities returned a legitimate 504 on the two-core runner.
-    // The overlap assertion below prevents shrinking it into a sequential test.
-    for i in 1..1_000 {
-        source.push_str(&format!(
-            "oa_activity a{i} \"Activity {i}\" {{ parent @a{}; }}\n",
-            i - 1
-        ));
-    }
-    source.push('}');
-    let client = server.client.clone();
-    let url = server.url(&format!("/projects/{id}/source"));
-    let stale_etag = etag.clone();
-    let proposed = tokio::spawn(async move {
-        client
-            .put(url)
-            .header("if-match", stale_etag)
-            .header("content-type", "text/plain")
-            .body(source)
-            .send()
-            .await
-            .unwrap()
-    });
-    tokio::time::sleep(std::time::Duration::from_millis(100)).await;
-    assert!(
-        !proposed.is_finished(),
-        "fixture must overlap actual candidate preparation"
-    );
-    let catalog = tokio::time::timeout(
-        std::time::Duration::from_secs(2),
-        server.client.get(server.url("/projects")).send(),
-    )
-    .await
-    .expect("catalog locked during valid candidate preparation")
-    .unwrap();
-    assert_eq!(catalog.status(), StatusCode::OK);
-    let winner = tokio::time::timeout(
-        std::time::Duration::from_secs(2),
-        server
-            .client
-            .patch(server.url(&format!("/projects/{id}")))
-            .header("if-match", &etag)
-            .json(&json!({"name":"Concurrent accepted review"}))
-            .send(),
-    )
-    .await
-    .expect("unrelated preparation held the commit lock")
-    .unwrap();
-    assert_eq!(winner.status(), StatusCode::OK);
-    // The two-second read/PATCH bounds above test responsiveness and lock
-    // ownership. Finishing the deliberately expensive admitted candidate is
-    // a separate watchdog, not a latency promise under parallel CPU contention.
-    let loser = tokio::time::timeout(std::time::Duration::from_secs(45), proposed)
-        .await
-        .expect("admitted candidate did not complete within the test watchdog")
-        .unwrap();
-    assert_eq!(loser.status(), StatusCode::PRECONDITION_FAILED);
-    let failure: Value = loser.json().await.unwrap();
-    assert_eq!(failure["code"], "revision_conflict");
-    assert_eq!(failure["current_revision"], 2);
-    let committed = server.get(id).await;
-    assert_eq!(committed.revision, 2);
-    assert_eq!(committed.model.name, "Concurrent accepted review");
-    assert!(committed.model.elements.is_empty());
-    let installed: StoredProject = serde_json::from_slice(
-        &std::fs::read(directory.path().join(format!("{id}.json"))).unwrap(),
-    )
-    .unwrap();
-    assert_eq!(installed.model, committed.model);
-    assert_eq!(installed.revision, 2);
-    server.stop().await;
-}
-
 #[tokio::test]
 async fn mission_and_contextual_chain_records_round_trip_and_edit_through_http() {
     let directory = tempfile::tempdir().unwrap();
@@ -2019,7 +1938,7 @@ async fn current_migration_reports_and_invalid_typed_transaction_preserve_http_s
         .text()
         .await
         .unwrap();
-    assert!(source.starts_with("arcadia 6;"));
+    assert!(source.starts_with("arcadia 7;"));
     assert_eq!(oa_core::language::parse(&source).unwrap(), stored.model);
     let no_op = server
         .client