ui/phase-27: battle viewer (radial scene, playback, map markers)

Engine wire change: Report.battle switched from []uuid.UUID to
[]BattleSummary{id, planet, shots} so the map can place battle
markers without N extra fetches. FBS schema + generated Go/TS
regenerated; transcoder + report controller updated; openapi
adds the BattleSummary schema with a freeze test.

Backend gateway forwards engine GET /api/v1/battle/:turn/:uuid as
/api/v1/user/games/{game_id}/battles/{turn}/{battle_id} (handler
plus engineclient.FetchBattle, contract test stub, openapi spec).

UI:
- BattleViewer (lib/battle-player/) is a logically isolated SVG
  radial scene that consumes a BattleReport prop. Planet at the
  centre, races on the outer ring at equal angular spacing, race
  clusters by (race, className) with <class>:<numLeft> labels;
  observer groups (inBattle: false) are not drawn; eliminated
  races drop out and survivors re-distribute on the next frame.
- Shot line per frame: red on destroyed, green otherwise; erased
  on the next frame. Playback controls: play/pause + step ± +
  rewind + 1x/2x/4x speed (400/200/100 ms per frame).
- Page wrapper (lib/active-view/battle.svelte) loads BattleReport
  via api/battle-fetch.ts; synthetic-gameId prefix routes to a
  fixture loader, otherwise REST through the gateway. Always-
  visible <ol> text protocol satisfies the accessibility ask.
- section-battles.svelte links every battle UUID into the viewer.
- map/battle-markers.ts: yellow X cross of 2 LinePrim through the
  corners of the planet's circumscribed square (stroke width
  clamps from 1 px at 1 shot to 5 px at 100+ shots); bombing
  marker is a stroke-only ring (yellow when damaged, red when
  wiped). Wired into state-binding.ts; click handler dispatches
  battle clicks to the viewer and bombing clicks to the matching
  Reports row.
- i18n keys for the viewer in en + ru.

Docs: ui/docs/battle-viewer-ux.md, FUNCTIONAL.md §6.5 + ru
mirror, ui/PLAN.md Phase 27 decisions + deferred TODOs (push
event, richer class visuals, animated re-distribution).

Tests: Vitest unit (radial layout + timeline frame builder +
marker stroke formula + marker primitives), Playwright e2e for
the viewer (Reports link → viewer, playback step, not-found),
backend engineclient FetchBattle (200 / 404 / bad input), engine
openapi freezes (BattleReport, BattleReportGroup,
BattleActionReport, BattleSummary, Report.battle items).

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

ui/frontend/src/lib/active-view/report/section-battles.svelte

@@ -1,13 +1,14 @@
 <!--
-Phase 23 Report View — battles section. The wire only carries
-battle UUIDs (the full battle report is fetched lazily by Phase 27),
-so each row is a monospace, non-interactive `<span>` of the battle
-identifier. Phase 27 will turn each row into a link to
-`/games/<id>/battle/<uuid>`; until then dead links are worse than
-plain text.
+Phase 27 Report View — battles section. Each row is a link into the
+Battle Viewer at `/games/<id>/battle/<uuid>?turn=<turn>` where
+`turn` follows the current report's turn so history-mode views land
+on the right battle. Phase 23 rendered the same rows as inactive
+monospace `<span>`; the rewire here is the one-liner the Phase 23
+decision log called out.
 -->
 <script lang="ts">
 	import { getContext } from "svelte";
+	import { page } from "$app/state";
 
 	import { i18n } from "$lib/i18n/index.svelte";
 	import {
@@ -19,7 +20,9 @@ plain text.
 		RENDERED_REPORT_CONTEXT_KEY,
 	);
 	const report = $derived(rendered?.report ?? null);
-	const ids = $derived(report?.battleIds ?? []);
+	const battles = $derived(report?.battles ?? []);
+	const gameId = $derived(page.params.id ?? "");
+	const turn = $derived(report?.turn ?? 0);
 </script>
 
 <section
@@ -31,22 +34,23 @@ plain text.
 
 	{#if report === null}
 		<p class="status">{i18n.t("game.report.loading")}</p>
-	{:else if ids.length === 0}
+	{:else if battles.length === 0}
 		<p class="status" data-testid="battles-empty">
 			{i18n.t("game.report.section.battles.empty")}
 		</p>
 	{:else}
 		<ul class="ids" data-testid="battles-list">
-			{#each ids as id (id)}
+			{#each battles as b (b.id)}
 				<li>
 					<span class="label">
 						{i18n.t("game.report.section.battles.id_label")}
 					</span>
-					<span
+					<a
 						class="uuid"
+						href={`/games/${gameId}/battle/${b.id}?turn=${turn}`}
 						data-testid="report-battle-row"
-						data-id={id}
-					>{id}</span>
+						data-id={b.id}
+					>{b.id}</a>
 				</li>
 			{/each}
 		</ul>
@@ -87,5 +91,10 @@ plain text.
 	.uuid {
 		color: #cfd7ff;
 		font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
+		text-decoration: underline;
+		text-underline-offset: 2px;
+	}
+	.uuid:hover {
+		color: #ffffff;
 	}
 </style>