test(ui): align rejected-submit e2e specs with per-command sync semantics

The `rename-planet` and `ship-classes` rejected-submit specs broke on
the previous commit because:

1. `tests/e2e/fixtures/order-fbs.ts` builds the FBS response without
   `forceDefaults(true)`, and flatbuffers@25's TS codegen now elides
   `cmd_applied=false` against its int8 default of 0. The encoded
   payload no longer carried the rejection, so the UI decoded the row
   as `applied` and the assertions on the `rejected` status text
   failed first. The production Go transcoder already force-slots
   the field; mirror that behaviour in the e2e fixture.
2. The specs themselves still asserted the old blanket
   `data-sync-status="error"` on per-command rejection. After the
   previous commit's behaviour change the bar stays `synced` for
   per-command rejection (only genuine transport failures keep the
   red banner + Retry), so the assertions now read the row's inline
   reason text instead.

`tests/e2e/fixtures/order-fbs.ts` also gains the `cmdErrorMessage`
field so future fixtures can mirror the engine's rejection reason
through the round trip.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

ui/frontend/tests/e2e/rename-planet.spec.ts

@@ -137,6 +137,9 @@ async function mockGateway(page: Page, opts: MockOpts): Promise<MockHandle> {
 							name: submittedName,
 							applied,
 							errorCode: applied ? null : 1,
+							errorMessage: applied
+								? null
+								: "Entity does not exists: planet #99",
 						});
 					}
 					if (opts.submitOutcome === "applied") {
@@ -320,14 +323,19 @@ test("rejected submit keeps the old name and surfaces the failure", async ({
 	const orderTool = page.getByTestId("sidebar-tool-order");
 
 	// The auto-sync pipeline reaches the server immediately after
-	// the inline confirm; the rejected verdict surfaces through the
-	// per-row status badge and the sync bar.
+	// the inline confirm. Per-command rejection is a player-correctable
+	// state: the round trip succeeded, the engine just refused this
+	// command, so the sync bar stays `synced` while the rejected row
+	// surfaces the engine-formatted reason for the player.
 	await expect(orderTool.getByTestId("order-command-status-0")).toHaveText(
 		"rejected",
 	);
+	await expect(orderTool.getByTestId("order-command-error-0")).toHaveText(
+		"Entity does not exists: planet #99",
+	);
 	await expect(orderTool.getByTestId("order-sync")).toHaveAttribute(
 		"data-sync-status",
-		"error",
+		"synced",
 	);
 
 	await page.getByTestId("sidebar-tab-inspector").click();