ui/phase-19: ship-group decoder + map binding + selection store

Wires Phase 19's data and rendering layers without yet adding the
inspector UI:

  - game-state.ts grows ReportLocalShipGroup / ReportOtherShipGroup
    / ReportIncomingShipGroup / ReportUnidentifiedShipGroup /
    ReportLocalFleet types and walks the matching FlatBuffers
    vectors (LocalGroup, OtherGroup, IncomingGroup,
    UnidentifiedGroup, LocalFleet) inside decodeReport. The Tech
    map is folded into the fixed-shape ShipGroupTech struct;
    cargo strings normalise to the closed CargoLoadType | "NONE"
    union; UUIDs come back as canonical 36-char strings.
  - synthetic-report.ts mirrors the new fields so the DEV-only
    lobby loader can feed JSON produced by legacy-report-to-json
    straight into the live UI surface.
  - selection.svelte.ts widens its discriminated union with a
    `kind: "shipGroup"` branch carrying a ShipGroupRef
    (local UUID / other / incoming / unidentified by index).
  - world.ts adds Style.strokeDashPx and render.ts.drawLine
    honours it via manual segmentation (PixiJS v8 has no native
    dash API). Ignored on points and circles.
  - state-binding.ts now returns { world, hitLookup }: the
    hit-lookup map keys every primitive id back to a concrete
    HitTarget so the click handler can dispatch to selectPlanet
    or selectShipGroup. Ship-group primitives live in a separate
    ship-groups.ts that emits one point per local / other /
    unidentified group, plus a dashed origin→destination line +
    clickable point per incoming group. Position is interpolated
    along the trajectory for in-hyperspace groups.
  - map.svelte threads the hitLookup into handleMapClick.

Vitest:
  - tests/helpers/empty-ship-groups.ts exposes EMPTY_SHIP_GROUPS
    so existing fixtures can spread the new five empty arrays
    without enumerating every field.
  - state-binding-groups.test.ts covers each group variant's
    primitive geometry and lookup correctness.
  - All previously-existing fixture builders pick up the spread
    so GameReport stays a complete object.

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

ui/frontend/src/api/synthetic-report.ts

@@ -20,10 +20,18 @@
 
 import type {
 	GameReport,
+	ReportIncomingShipGroup,
+	ReportLocalFleet,
+	ReportLocalShipGroup,
+	ReportOtherShipGroup,
 	ReportPlanet,
 	ReportRoute,
+	ReportUnidentifiedShipGroup,
 	ShipClassSummary,
+	ShipGroupTech,
 } from "./game-state";
+import type { CargoLoadType } from "../sync/order-types";
+import { isCargoLoadType } from "../sync/order-types";
 
 export const SYNTHETIC_GAME_ID_PREFIX = "synthetic-";
 
@@ -96,6 +104,45 @@ interface SyntheticPlayer {
 	cargo: number;
 }
 
+interface SyntheticShipGroup {
+	id?: string;
+	number?: number;
+	class?: string;
+	tech?: Record<string, number>;
+	cargo?: string;
+	load?: number;
+	destination?: number;
+	origin?: number;
+	range?: number;
+	speed?: number;
+	mass?: number;
+	state?: string;
+	fleet?: string;
+}
+
+interface SyntheticIncomingGroup {
+	origin?: number;
+	destination?: number;
+	distance?: number;
+	speed?: number;
+	mass?: number;
+}
+
+interface SyntheticUnidentifiedGroup {
+	x?: number;
+	y?: number;
+}
+
+interface SyntheticLocalFleet {
+	name?: string;
+	groups?: number;
+	destination?: number;
+	origin?: number;
+	range?: number;
+	speed?: number;
+	state?: string;
+}
+
 interface SyntheticReportRoot {
 	turn?: number;
 	mapWidth?: number;
@@ -108,6 +155,11 @@ interface SyntheticReportRoot {
 	uninhabitedPlanet?: SyntheticPlanet[];
 	unidentifiedPlanet?: SyntheticPlanet[];
 	localShipClass?: SyntheticShipClass[];
+	localGroup?: SyntheticShipGroup[];
+	otherGroup?: SyntheticShipGroup[];
+	incomingGroup?: SyntheticIncomingGroup[];
+	unidentifiedGroup?: SyntheticUnidentifiedGroup[];
+	localFleet?: SyntheticLocalFleet[];
 }
 
 function decodeSyntheticReport(json: unknown): GameReport {
@@ -146,6 +198,59 @@ function decodeSyntheticReport(json: unknown): GameReport {
 
 	const routes: ReportRoute[] = [];
 
+	const localShipGroups: ReportLocalShipGroup[] = (root.localGroup ?? []).map(
+		(g, i) => ({
+			id: typeof g.id === "string" ? g.id : `synthetic-local-group-${i}`,
+			count: numOr0(g.number),
+			class: typeof g.class === "string" ? g.class : "",
+			tech: toShipGroupTech(g.tech),
+			cargo: toCargoType(g.cargo),
+			load: numOr0(g.load),
+			destination: numOr0(g.destination),
+			origin: typeof g.origin === "number" ? g.origin : null,
+			range: typeof g.range === "number" ? g.range : null,
+			speed: numOr0(g.speed),
+			mass: numOr0(g.mass),
+			state: typeof g.state === "string" ? g.state : "",
+			fleet: typeof g.fleet === "string" ? g.fleet : null,
+		}),
+	);
+	const otherShipGroups: ReportOtherShipGroup[] = (root.otherGroup ?? []).map(
+		(g) => ({
+			count: numOr0(g.number),
+			class: typeof g.class === "string" ? g.class : "",
+			tech: toShipGroupTech(g.tech),
+			cargo: toCargoType(g.cargo),
+			load: numOr0(g.load),
+			destination: numOr0(g.destination),
+			origin: typeof g.origin === "number" ? g.origin : null,
+			range: typeof g.range === "number" ? g.range : null,
+			speed: numOr0(g.speed),
+			mass: numOr0(g.mass),
+		}),
+	);
+	const incomingShipGroups: ReportIncomingShipGroup[] = (
+		root.incomingGroup ?? []
+	).map((g) => ({
+		origin: numOr0(g.origin),
+		destination: numOr0(g.destination),
+		distance: numOr0(g.distance),
+		speed: numOr0(g.speed),
+		mass: numOr0(g.mass),
+	}));
+	const unidentifiedShipGroups: ReportUnidentifiedShipGroup[] = (
+		root.unidentifiedGroup ?? []
+	).map((g) => ({ x: numOr0(g.x), y: numOr0(g.y) }));
+	const localFleets: ReportLocalFleet[] = (root.localFleet ?? []).map((f) => ({
+		name: typeof f.name === "string" ? f.name : "",
+		groupCount: numOr0(f.groups),
+		destination: numOr0(f.destination),
+		origin: typeof f.origin === "number" ? f.origin : null,
+		range: typeof f.range === "number" ? f.range : null,
+		speed: numOr0(f.speed),
+		state: typeof f.state === "string" ? f.state : "",
+	}));
+
 	return {
 		turn: numOr0(root.turn),
 		mapWidth: numOr0(root.mapWidth),
@@ -159,9 +264,30 @@ function decodeSyntheticReport(json: unknown): GameReport {
 		localPlayerWeapons: tech.weapons,
 		localPlayerShields: tech.shields,
 		localPlayerCargo: tech.cargo,
+		localShipGroups,
+		otherShipGroups,
+		incomingShipGroups,
+		unidentifiedShipGroups,
+		localFleets,
 	};
 }
 
+function toShipGroupTech(raw: Record<string, number> | undefined): ShipGroupTech {
+	const out: ShipGroupTech = { drive: 0, weapons: 0, shields: 0, cargo: 0 };
+	if (raw === undefined || raw === null) return out;
+	if (typeof raw.drive === "number") out.drive = raw.drive;
+	if (typeof raw.weapons === "number") out.weapons = raw.weapons;
+	if (typeof raw.shields === "number") out.shields = raw.shields;
+	if (typeof raw.cargo === "number") out.cargo = raw.cargo;
+	return out;
+}
+
+function toCargoType(raw: string | undefined): CargoLoadType | "NONE" {
+	if (raw === undefined || raw === "" || raw === "-") return "NONE";
+	if (isCargoLoadType(raw)) return raw;
+	return "NONE";
+}
+
 function toPlanet(
 	p: SyntheticPlanet,
 	kind: ReportPlanet["kind"],