Update migration agent documentation

Author: suntala

agent-docs/resources/sdkv2-to-framework-migration.md

@@ -196,6 +196,10 @@ func (r *fooResource) Delete(ctx context.Context, req resource.DeleteRequest, re
 
 Factoring out a private `r.read(ctx, id string) (*resourceFooModel, diag.Diagnostics)` method is strongly recommended — it is reused by `Read`, `Create` (read-back), `Update` (read-back), and `ImportState`.
 
+**Org-scoped IDs — avoid copy-paste parsing:** If `read`, `Update`, and `Delete` all call `r.clientFromExistingOrgResource(resourceFooID, ...)` and then validate `split` length, type-assert the resource-local id (string, int, etc.), and surface the same diagnostics, extract a **single private helper** (for example `(client, orgID, uid, diags)` for a uid-based resource). That keeps behavior aligned and matches what reviewers expect after several migrations.
+
+**Create — string UID vs numeric fallback:** Some APIs return a primary string identifier and sometimes a legacy numeric id. If you mirror the old SDK pattern `uid := payload.UID; if uid == "" { uid = strconv.FormatInt(payload.ID, 10) }`, only use the numeric branch when **`payload.ID != 0`**. If both are empty/zero, **return a diagnostic** instead of building a composite Terraform id containing `"0"` or another bogus value.
+
 #### 2g. ImportState
 
 ```go