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/src/sync/order-load.ts

@@ -63,6 +63,17 @@ export class OrderLoadError extends Error {
 
 export interface FetchedOrder {
 	commands: OrderCommand[];
+	// Per-command status keyed by cmdId. Populated from the engine's
+	// stored order so a returning player sees the same per-command
+	// verdict (applied / rejected) the previous submission produced —
+	// not a synthetic "applied" derived from the local cache.
+	statuses: Map<string, "applied" | "rejected">;
+	// Per-command engine-formatted error code/message, keyed by cmdId.
+	// Both maps carry an entry for every loaded command; the value is
+	// null when the command was applied (no error). The message lets
+	// the UI surface the rejection reason without a code → text catalog.
+	errorCodes: Map<string, number | null>;
+	errorMessages: Map<string, string | null>;
 	updatedAt: number;
 }
 
@@ -119,7 +130,13 @@ function decodeResponse(payload: Uint8Array): FetchedOrder {
 	const buffer = new ByteBuffer(payload);
 	const response = UserGamesOrderGetResponse.getRootAsUserGamesOrderGetResponse(buffer);
 	if (!response.found()) {
-		return { commands: [], updatedAt: 0 };
+		return {
+			commands: [],
+			statuses: new Map(),
+			errorCodes: new Map(),
+			errorMessages: new Map(),
+			updatedAt: 0,
+		};
 	}
 	const order = response.order();
 	if (order === null) {
@@ -130,6 +147,9 @@ function decodeResponse(payload: Uint8Array): FetchedOrder {
 		);
 	}
 	const commands: OrderCommand[] = [];
+	const statuses = new Map<string, "applied" | "rejected">();
+	const errorCodes = new Map<string, number | null>();
+	const errorMessages = new Map<string, string | null>();
 	const length = order.commandsLength();
 	for (let i = 0; i < length; i++) {
 		const item = order.commands(i);
@@ -137,9 +157,20 @@ function decodeResponse(payload: Uint8Array): FetchedOrder {
 		const cmd = decodeCommand(item);
 		if (cmd === null) continue;
 		commands.push(cmd);
+		// The engine echoes `cmd_applied = false` only when the order
+		// was rejected per-command; missing / true both mean applied.
+		const applied = item.cmdApplied();
+		statuses.set(cmd.id, applied === false ? "rejected" : "applied");
+		const code = item.cmdErrorCode();
+		errorCodes.set(cmd.id, code === null ? null : Number(code));
+		const msg = item.cmdErrorMessage();
+		errorMessages.set(cmd.id, msg === null ? null : msg);
 	}
 	return {
 		commands,
+		statuses,
+		errorCodes,
+		errorMessages,
 		updatedAt: Number(order.updatedAt()),
 	};
 }