feat(FN-3947): move github tracking section to bottom of task form

Moved the GitHub tracking section to the bottom of the task form and locked its field order, with supporting tests covering the new placement in both NewTaskModal and TaskForm components, plus documentation updates for the new form layout.

Fusion-Task-Id: FN-3947

packages/core/src/__tests__/store.test.ts

@@ -10472,7 +10472,7 @@ Task with acceptance criteria
       } finally {
         store.stopWatching();
       }
-    });
+    }, 30_000);
   });
 
   describe("async checkForChanges", () => {