feat(game): race exit warnings in the turn report (#12)

Surface the inactivity-removal countdown the rules promise but the
engine never reported. A race within five turns of being auto-removed
for inactivity gets a personal warning in its own report; every race
within three turns is listed publicly to all participants.

- model: Report.PersonalExitWarning + RacesLeavingSoon ([]RaceExitNotice)
- fbs: RaceExitNotice table + Report.personal_exit_warning /
  races_leaving_soon (regenerated Go + TS bindings)
- transcoder: encode/decode both fields
- engine: ReportExitWarnings fills the recipient's TTL (1..5) and lists
  other non-extinct races with TTL 1..3, excluding the recipient itself
- ui: danger-styled personal banner + "races leaving soon" section
  (hidden when empty), wired into the report view, EN/RU i18n
- docs: rules.txt report-section list, FUNCTIONAL.md 6.4 + RU mirror

Voluntary quit and idle timeout share the TTL countdown and are not
distinguished, per the agreed scope.

ui/frontend/tests/report-section-race-exit-warnings.test.ts

@@ -0,0 +1,130 @@
+// Vitest coverage for the report view's race-exit-warnings section and
+// the personal exit-warning banner. The section lists other races
+// within a few turns of inactivity removal and hides entirely when the
+// list is empty; the banner shows the local race's own countdown only
+// when it is non-zero. Both read the report through the rendered-report
+// context, mirroring the other report sections.
+
+import "@testing-library/jest-dom/vitest";
+import { render } from "@testing-library/svelte";
+import { beforeEach, describe, expect, test } from "vitest";
+
+import { i18n } from "../src/lib/i18n/index.svelte";
+import type { GameReport } from "../src/api/game-state";
+import { RENDERED_REPORT_CONTEXT_KEY } from "../src/lib/rendered-report.svelte";
+import { EMPTY_SHIP_GROUPS } from "./helpers/empty-ship-groups";
+
+import SectionRaceExitWarnings from "../src/lib/active-view/report/section-race-exit-warnings.svelte";
+import PersonalExitBanner from "../src/lib/active-view/report/personal-exit-banner.svelte";
+
+beforeEach(() => {
+	i18n.resetForTests("en");
+});
+
+function makeReport(overrides: Partial<GameReport> = {}): GameReport {
+	return {
+		turn: 1,
+		mapWidth: 1000,
+		mapHeight: 1000,
+		planetCount: 0,
+		planets: [],
+		race: "Self",
+		localShipClass: [],
+		routes: [],
+		localPlayerDrive: 0,
+		localPlayerWeapons: 0,
+		localPlayerShields: 0,
+		localPlayerCargo: 0,
+		...EMPTY_SHIP_GROUPS,
+		...overrides,
+	};
+}
+
+function mount(
+	component: typeof SectionRaceExitWarnings | typeof PersonalExitBanner,
+	report: GameReport | null,
+) {
+	const context = new Map<unknown, unknown>([
+		[
+			RENDERED_REPORT_CONTEXT_KEY,
+			{
+				get report() {
+					return report;
+				},
+			},
+		],
+	]);
+	return render(component, { context });
+}
+
+describe("report race-exit-warnings section", () => {
+	test("renders nothing before the report lands", () => {
+		const ui = mount(SectionRaceExitWarnings, null);
+		expect(
+			ui.queryByTestId("report-section-race-exit-warnings"),
+		).not.toBeInTheDocument();
+	});
+
+	test("hides the section entirely when no races are leaving", () => {
+		const ui = mount(
+			SectionRaceExitWarnings,
+			makeReport({ racesLeavingSoon: [] }),
+		);
+		expect(
+			ui.queryByTestId("report-section-race-exit-warnings"),
+		).not.toBeInTheDocument();
+	});
+
+	test("lists each race with its remaining turns", () => {
+		const ui = mount(
+			SectionRaceExitWarnings,
+			makeReport({
+				racesLeavingSoon: [
+					{ race: "Bajori", turnsLeft: 2 },
+					{ race: "Cardassian", turnsLeft: 1 },
+				],
+			}),
+		);
+		expect(
+			ui.getByTestId("report-section-race-exit-warnings"),
+		).toBeInTheDocument();
+		const rows = ui.getAllByTestId("race-exit-warnings-row");
+		expect(rows).toHaveLength(2);
+		expect(rows[0]).toHaveAttribute("data-race", "Bajori");
+		expect(rows[0]).toHaveTextContent("Bajori");
+		expect(rows[0]).toHaveTextContent("2");
+		expect(rows[1]).toHaveAttribute("data-race", "Cardassian");
+		expect(rows[1]).toHaveTextContent("Cardassian");
+		expect(rows[1]).toHaveTextContent("1");
+	});
+});
+
+describe("personal exit-warning banner", () => {
+	test("renders nothing before the report lands", () => {
+		const ui = mount(PersonalExitBanner, null);
+		expect(
+			ui.queryByTestId("report-personal-exit-banner"),
+		).not.toBeInTheDocument();
+	});
+
+	test("stays hidden when there is no personal warning", () => {
+		const ui = mount(
+			PersonalExitBanner,
+			makeReport({ personalExitWarning: 0 }),
+		);
+		expect(
+			ui.queryByTestId("report-personal-exit-banner"),
+		).not.toBeInTheDocument();
+	});
+
+	test("shows the danger banner with the countdown when warned", () => {
+		const ui = mount(
+			PersonalExitBanner,
+			makeReport({ personalExitWarning: 3 }),
+		);
+		const banner = ui.getByTestId("report-personal-exit-banner");
+		expect(banner).toBeInTheDocument();
+		expect(banner).toHaveAttribute("role", "alert");
+		expect(banner).toHaveTextContent("3");
+	});
+});