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>

pkg/schema/fbs/order.fbs

@@ -193,6 +193,12 @@ table CommandItem {
   cmd_applied: bool = null;
   cmd_error_code: int64 = null;
   payload: CommandPayload (required);
+  // Human-readable failure reason returned by the engine when
+  // `cmd_applied = false`. Appended after `payload` to preserve the
+  // wire offsets of existing slots (FBS field IDs are allocated in
+  // declaration order, so inserting in the middle would shift every
+  // later slot). Omitted on requests and on applied commands.
+  cmd_error_message: string;
 }
 
 // UserGamesCommand is the signed-gRPC request payload for