ui/phase-25: backend turn-cutoff guard + auto-pause + UI sync protocol

Backend now owns the turn-cutoff and pause guards the order tab
relies on: the scheduler flips runtime_status between
generation_in_progress and running around every engine tick, a
failed tick auto-pauses the game through OnRuntimeSnapshot, and a
new game.paused notification kind fans out alongside
game.turn.ready. The user-games handlers reject submits with
HTTP 409 turn_already_closed or game_paused depending on the
runtime state.

UI delegates auto-sync to a new OrderQueue: offline detection,
single retry on reconnect, conflict / paused classification.
OrderDraftStore surfaces conflictBanner / pausedBanner runes,
clears them on local mutation or on a game.turn.ready push via
resetForNewTurn. The order tab renders the matching banners and
the new conflict per-row badge; i18n bundles cover en + ru.

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

backend/internal/runtime/orders_accept_test.go

@@ -0,0 +1,82 @@
+package runtime
+
+import (
+	"errors"
+	"testing"
+)
+
+// TestOrdersAcceptStatus pins down the Phase 25 pre-check that
+// gates the user-games command/order handlers against the runtime
+// record. The decision must distinguish a turn cutoff (engine is
+// producing) from a paused game so the UI can surface the right
+// banner; all other non-running runtime statuses collapse into
+// `ErrGamePaused`.
+func TestOrdersAcceptStatus(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name string
+		rec  RuntimeRecord
+		want error
+	}{
+		{
+			name: "running and not paused accepts orders",
+			rec:  RuntimeRecord{Status: RuntimeStatusRunning, Paused: false},
+			want: nil,
+		},
+		{
+			name: "running but paused returns game paused",
+			rec:  RuntimeRecord{Status: RuntimeStatusRunning, Paused: true},
+			want: ErrGamePaused,
+		},
+		{
+			name: "generation in progress returns turn already closed",
+			rec:  RuntimeRecord{Status: RuntimeStatusGenerationInProgress},
+			want: ErrTurnAlreadyClosed,
+		},
+		{
+			name: "generation failed returns game paused",
+			rec:  RuntimeRecord{Status: RuntimeStatusGenerationFailed},
+			want: ErrGamePaused,
+		},
+		{
+			name: "engine unreachable returns game paused",
+			rec:  RuntimeRecord{Status: RuntimeStatusEngineUnreachable},
+			want: ErrGamePaused,
+		},
+		{
+			name: "stopped returns game paused",
+			rec:  RuntimeRecord{Status: RuntimeStatusStopped},
+			want: ErrGamePaused,
+		},
+		{
+			name: "finished returns game paused",
+			rec:  RuntimeRecord{Status: RuntimeStatusFinished},
+			want: ErrGamePaused,
+		},
+		{
+			name: "removed returns game paused",
+			rec:  RuntimeRecord{Status: RuntimeStatusRemoved},
+			want: ErrGamePaused,
+		},
+		{
+			name: "starting returns game paused",
+			rec:  RuntimeRecord{Status: RuntimeStatusStarting},
+			want: ErrGamePaused,
+		},
+		{
+			name: "paused takes precedence over generation in progress",
+			rec:  RuntimeRecord{Status: RuntimeStatusGenerationInProgress, Paused: true},
+			want: ErrGamePaused,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+			got := OrdersAcceptStatus(tt.rec)
+			if !errors.Is(got, tt.want) {
+				t.Errorf("OrdersAcceptStatus = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}