fix(order): surface rejection reason, keep sync green, hydrate verdicts

Three issues surfaced once the per-command rejection from the previous
commit actually reached the UI:

1. Sync banner falsely red. `OrderDraftStore.runSync` flipped
   `syncStatus = "error"` whenever any command was rejected and
   advertised a Retry button. A per-command rejection is a
   player-correctable state — the round trip succeeded, the engine
   just refused that command — so the retry can't help. Keep
   `syncStatus = "synced"` on `success`; the red row highlight is
   the visible cue.

2. Rejection reason missing. Add `cmd_error_message: string` to
   `CommandItem` in `pkg/schema/fbs/order.fbs` (appended last to
   preserve existing slot offsets) and regenerate the Go + TS stubs
   for that one type. Plumb the message through `CommandMeta`,
   `Controller.applyCommand`'s `m.Result(code, message)` call, the
   Go transcoder, the UI decoders in `submit.ts` /  `order-load.ts`,
   and the `OrderDraftStore.errorMessages` map. `order-tab.svelte`
   renders it as an italic danger-coloured line under rejected
   commands, with new CSS for `.error-reason`.

3. Verdict lost on navigation. `order-load.ts.decodeCommand` never
   read `cmdApplied`/`cmdErrorCode`, so `hydrateFromServer` fell
   back to a blanket "applied" status — a previously-rejected
   command came back green after a lobby → game round trip. Extend
   the fetch decoder to populate `statuses`/`errorCodes`/
   `errorMessages` maps and have `hydrateFromServer` use them.
   Engine-side persistence already records the verdict on disk —
   verified against the live `0000/order/<id>.json`.

`flatbuffers@25` elides default-int8/int64 fields on write; the Go
transcoder force-slots `cmd_applied=false` / `cmd_error_code=0`
already, the new test fixtures flip `builder.forceDefaults(true)` to
mirror that behaviour so the round trip survives.

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

ui/frontend/tests/submit.test.ts

@@ -40,13 +40,28 @@ function mockClient(
 }
 
 function buildResponse(
-	commands: { id: string; applied: boolean | null; errorCode: number | null }[],
+	commands: {
+		id: string;
+		applied: boolean | null;
+		errorCode: number | null;
+		errorMessage?: string | null;
+	}[],
 	updatedAt: number,
 ): Uint8Array {
 	const builder = new Builder(256);
+	// flatbuffers@25 skips fields equal to their generated default when
+	// writing — the Go transcoder works around this via explicit
+	// `Slot()` calls. This fixture stands in for the engine + gateway,
+	// so we flip `forceDefaults` to keep `cmd_applied=false` (=== int8
+	// default 0) and `cmd_error_code=0` from being silently elided.
+	builder.forceDefaults(true);
 	const itemOffsets = commands.map((c) => {
 		const cmdIdOffset = builder.createString(c.id);
 		const nameOffset = builder.createString("ignored");
+		const errMsgOffset =
+			c.errorMessage !== undefined && c.errorMessage !== null
+				? builder.createString(c.errorMessage)
+				: 0;
 		const payloadOffset = CommandPlanetRename.createCommandPlanetRename(
 			builder,
 			BigInt(0),
@@ -60,6 +75,9 @@ function buildResponse(
 		}
 		CommandItem.addPayloadType(builder, CommandPayload.CommandPlanetRename);
 		CommandItem.addPayload(builder, payloadOffset);
+		if (errMsgOffset !== 0) {
+			CommandItem.addCmdErrorMessage(builder, errMsgOffset);
+		}
 		return CommandItem.endCommandItem(builder);
 	});
 	const commandsVec = UserGamesOrderResponse.createCommandsVector(builder, itemOffsets);