One last round of testing and documentation updates.

documentation/V3_FRONTEND_API_GUIDE.md

@@ -94,6 +94,61 @@ The `op` property in a `SearchFilter` supports the following values:
 
 ---
 
+## 3. Create, Update, & Delete (POST, PATCH, DELETE)
+
+V3 supports both top-level operations and nested parent/child operations.
+
+### A. Create (POST)
+When creating objects, V3 strictly validates the incoming JSON against the `mdl_in` Pydantic model.
+
+```ts
+// POST /v3/crud/{obj_type}/
+// POST /v3/crud/journal/
+export async function create_ae_obj_v3({ api_cfg, obj_type, data }) {
+    const endpoint = `/v3/crud/${obj_type}/`;
+    return await post_object({ api_cfg, endpoint, data });
+}
+
+// POST /v3/crud/{parent_obj_type}/{parent_obj_id}/{child_obj_type}/
+// POST /v3/crud/journal/EIAC-40-76-82/journal_entry/
+// Note: Parent ID is automatically injected into the child record.
+export async function create_nested_obj_v3({ api_cfg, parent_type, parent_id, child_type, data }) {
+    const endpoint = `/v3/crud/${parent_type}/${parent_id}/${child_type}/`;
+    return await post_object({ api_cfg, endpoint, data });
+}
+```
+
+### B. Update (PATCH)
+V3 uses `PATCH` for partial updates. Only the fields provided in the body will be modified in the database.
+
+```ts
+// PATCH /v3/crud/{obj_type}/{obj_id}
+export async function update_ae_obj_v3({ api_cfg, obj_type, obj_id, data }) {
+    const endpoint = `/v3/crud/${obj_type}/${obj_id}`;
+    return await patch_object({ api_cfg, endpoint, data });
+}
+
+// PATCH /v3/crud/{parent_type}/{parent_id}/{child_type}/{child_id}
+// Verification: The backend ensures the child actually belongs to the parent before updating.
+export async function update_nested_obj_v3({ api_cfg, parent_type, parent_id, child_type, child_id, data }) {
+    const endpoint = `/v3/crud/${parent_type}/${parent_id}/${child_type}/${child_id}`;
+    return await patch_object({ api_cfg, endpoint, data });
+}
+```
+
+### C. Delete (DELETE)
+The `DELETE` method is used for removal. The backend may implement soft-delete (hide/disable) depending on the configuration.
+
+```ts
+// DELETE /v3/crud/{obj_type}/{obj_id}
+export async function delete_ae_obj_v3({ api_cfg, obj_type, obj_id }) {
+    const endpoint = `/v3/crud/${obj_type}/${obj_id}`;
+    return await delete_object({ api_cfg, endpoint });
+}
+```
+
+---
+
 ## 4. Authentication in V3
 
 V3 supports multiple authentication methods. The backend resolves these automatically.