ui/phase-19: torus-aware incoming track + on-planet groups in inspector

Two follow-up fixes after the initial Phase 19 landing:

  1. The IncomingGroup dashed trajectory was drawn between raw
     (x1, y1) and (x2, y2) world coordinates. On torus wrap mode
     this took the long way around when origin and destination
     sat near opposite seams. The line now picks endpoints via
     `torusShortestDelta` so the segment crosses the seam when
     that's the shorter visual path. The interpolated clickable
     point follows the same unwrapped vector. The same helper
     fixes the in-hyperspace position for local / foreign groups.
  2. On-planet local and foreign groups previously rendered as
     small offset points next to every populated planet, which
     turned the canvas into noise as soon as a player held more
     than a handful of planets. The map no longer renders any
     in-orbit group; the planet inspector grows a compact
     "stationed ship groups" subsection
     (`lib/inspectors/planet/ship-groups.svelte`) that lists
     each in-orbit group as a row of `<race> · <class> · <count>
     ships · <mass>`. Race attribution: LocalGroup → the player's
     race, OtherGroup on a foreign-owned planet → the planet's
     owner, OtherGroup elsewhere → "foreign" placeholder. Rows
     are non-interactive in Phase 19; Phase 21+ will deep-link
     into the ship-groups table view with a (planet, race) filter.

Tests:
  - `state-binding-groups.test.ts` swaps the on-planet rendering
    expectation for the new "no map primitive" rule, and adds a
    regression that asserts the incoming line crosses the torus
    seam via `torusShortestDelta`.
  - new `inspector-planet-ship-groups.test.ts` covers row
    composition, the destination-mismatch filter, the
    in-hyperspace exclusion, the foreign-planet owner fallback,
    and the empty-state collapse.
  - `inspector-planet.test.ts` and `inspector-ship-group.spec.ts`
    pick up the new prop chain (`localShipGroups`,
    `otherShipGroups`, `localRace`).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

ui/frontend/src/lib/inspectors/planet/ship-groups.svelte

@@ -0,0 +1,144 @@
+<!--
+Phase 19 read-only "ship groups stationed here" subsection of the
+planet inspector. Phase 19 originally rendered every in-orbit group
+as an offset point near its planet on the map, which crowded the
+canvas to the point of unreadability. The map now hides on-planet
+groups and the planet inspector lists them instead — one row per
+group, showing its race, class, ship count, and mass.
+
+Race attribution is best-effort:
+  - LocalGroup → the player's own race (`localRace` prop).
+  - OtherGroup on an `other`-kind planet → the planet's owner.
+  - OtherGroup elsewhere → "foreign" placeholder; the engine's
+    typed contract does not carry per-group ownership outside
+    battle rosters.
+
+Rows are intentionally non-interactive in Phase 19. Phase 21+ will
+deliver a full ship-groups table view; clicking a row will then
+deep-link into that table with a `(planet, race)` filter pre-applied.
+-->
+<script lang="ts">
+	import type {
+		ReportLocalShipGroup,
+		ReportOtherShipGroup,
+		ReportPlanet,
+	} from "../../../api/game-state";
+	import { i18n } from "$lib/i18n/index.svelte";
+
+	type Props = {
+		planet: ReportPlanet;
+		localShipGroups: ReportLocalShipGroup[];
+		otherShipGroups: ReportOtherShipGroup[];
+		localRace: string;
+	};
+	let { planet, localShipGroups, otherShipGroups, localRace }: Props = $props();
+
+	interface StationedRow {
+		key: string;
+		race: string;
+		class: string;
+		count: number;
+		mass: number;
+	}
+
+	const stationedRows: StationedRow[] = $derived.by(() => {
+		const rows: StationedRow[] = [];
+		for (const g of localShipGroups) {
+			if (g.destination !== planet.number) continue;
+			if (g.origin !== null || g.range !== null) continue;
+			rows.push({
+				key: `local:${g.id}`,
+				race: localRace || i18n.t("game.inspector.planet.ship_groups.race.unknown"),
+				class: g.class,
+				count: g.count,
+				mass: g.mass,
+			});
+		}
+		const foreignRace =
+			planet.owner ??
+			i18n.t("game.inspector.planet.ship_groups.race.foreign");
+		for (let i = 0; i < otherShipGroups.length; i++) {
+			const g = otherShipGroups[i]!;
+			if (g.destination !== planet.number) continue;
+			if (g.origin !== null || g.range !== null) continue;
+			rows.push({
+				key: `other:${i}`,
+				race: foreignRace,
+				class: g.class,
+				count: g.count,
+				mass: g.mass,
+			});
+		}
+		return rows;
+	});
+
+	function formatNumber(value: number): string {
+		return value.toLocaleString(undefined, { maximumFractionDigits: 2 });
+	}
+</script>
+
+{#if stationedRows.length > 0}
+	<section class="ship-groups" data-testid="inspector-planet-ship-groups">
+		<h4>{i18n.t("game.inspector.planet.ship_groups.title")}</h4>
+		<ul class="rows">
+			{#each stationedRows as row (row.key)}
+				<li class="row" data-testid="inspector-planet-ship-groups-row">
+					<span class="race" data-testid="inspector-planet-ship-groups-race">
+						{row.race}
+					</span>
+					<span class="class">{row.class}</span>
+					<span class="count">
+						{i18n.t("game.inspector.planet.ship_groups.row.count", {
+							count: String(row.count),
+						})}
+					</span>
+					<span class="mass">
+						{i18n.t("game.inspector.planet.ship_groups.row.mass", {
+							mass: formatNumber(row.mass),
+						})}
+					</span>
+				</li>
+			{/each}
+		</ul>
+	</section>
+{/if}
+
+<style>
+	.ship-groups {
+		display: flex;
+		flex-direction: column;
+		gap: 0.4rem;
+	}
+	h4 {
+		margin: 0;
+		font-size: 0.85rem;
+		text-transform: uppercase;
+		letter-spacing: 0.05em;
+		color: #aab;
+	}
+	.rows {
+		list-style: none;
+		margin: 0;
+		padding: 0;
+		display: flex;
+		flex-direction: column;
+		gap: 0.2rem;
+	}
+	.row {
+		display: grid;
+		grid-template-columns: 1fr 1fr auto auto;
+		gap: 0.5rem;
+		font-size: 0.85rem;
+		font-variant-numeric: tabular-nums;
+	}
+	.race {
+		font-weight: 600;
+	}
+	.class {
+		color: #cdd;
+	}
+	.count,
+	.mass {
+		color: #aab;
+	}
+</style>