fix(ui-map): repaint fog as layered overpaint; rename to visibleHyperspace

The Phase 29 fog overlay rendered as a handful of random arc
segments instead of a clean union of holes around LOCAL planets
— Pixi v8's `Graphics.cut()` does not reliably subtract multiple
overlapping circles from a base path.

Replaced the cut-based approach with a layered overpaint: a
fog-tinted rectangle fills the world, then opaque background-
coloured circles are painted on top for every visibility circle.
The natural rendering order unions overlapping circles for free —
no geometry, no `cut()` quirks, one extra fill per circle.

Renamed the toggle from `visibilityFog` to `visibleHyperspace`
across the store, i18n strings, popover, tests, and docs. The
overlay still implements the visual "fog" effect at the renderer
level (FOG_COLOR, setVisibilityFog, getMapFog); the toggle is
named after the player-facing concept it controls — the portion
of the map that is visible (intelligence/scan coverage) — rather
than the obscured part.

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

ui/frontend/src/lib/active-view/map-toggles.svelte

@@ -185,11 +185,11 @@ bottom-tabs bar.
 				<label>
 					<input
 						type="checkbox"
-						data-testid="map-toggles-visibility-fog"
-						checked={store.mapToggles.visibilityFog}
-						onchange={(e) => setFlag("visibilityFog", e)}
+						data-testid="map-toggles-visible-hyperspace"
+						checked={store.mapToggles.visibleHyperspace}
+						onchange={(e) => setFlag("visibleHyperspace", e)}
 					/>
-					<span>{i18n.t("game.map.toggles.visibility_fog")}</span>
+					<span>{i18n.t("game.map.toggles.visible_hyperspace")}</span>
 				</label>
 				<div class="wrap-row">
 					<span class="wrap-label">{i18n.t("game.map.toggles.wrap.label")}</span>

ui/frontend/src/lib/active-view/map.svelte

@@ -193,7 +193,7 @@ preference the store already manages.
 		void toggles.cargoRoutes;
 		void toggles.battleMarkers;
 		void toggles.bombingMarkers;
-		void toggles.visibilityFog;
+		void toggles.visibleHyperspace;
 
 		// Phase 29 visibility derivation. Cargo routes and pending-
 		// Send overlay are extras (no Pixi remount on flip); the

ui/frontend/src/lib/game-state.svelte.ts

@@ -57,7 +57,14 @@ export interface MapToggles {
 	cargoRoutes: boolean;
 	battleMarkers: boolean;
 	bombingMarkers: boolean;
-	visibilityFog: boolean;
+	/**
+	 * visibleHyperspace toggles the foggy overlay that darkens the
+	 * world OUTSIDE the union of `VisibilityDistance` circles around
+	 * LOCAL planets. The visible part of the map — the player's
+	 * intelligence/scan coverage — stays in the regular background
+	 * colour; everything else looks "foggy". Default ON.
+	 */
+	visibleHyperspace: boolean;
 }
 
 export const DEFAULT_MAP_TOGGLES: MapToggles = {
@@ -71,7 +78,7 @@ export const DEFAULT_MAP_TOGGLES: MapToggles = {
 	cargoRoutes: true,
 	battleMarkers: true,
 	bombingMarkers: true,
-	visibilityFog: true,
+	visibleHyperspace: true,
 };
 
 interface PersistedMapToggles {

ui/frontend/src/lib/i18n/locales/en.ts

@@ -128,7 +128,7 @@ const en = {
 	"game.map.toggles.uninhabited_planets": "uninhabited planets",
 	"game.map.toggles.unidentified_planets": "unidentified planets",
 	"game.map.toggles.unreachable_planets": "show unreachable planets",
-	"game.map.toggles.visibility_fog": "visibility fog",
+	"game.map.toggles.visible_hyperspace": "visible hyperspace",
 	"game.map.toggles.wrap.label": "wrap scrolling",
 	"game.map.toggles.wrap.torus": "torus",
 	"game.map.toggles.wrap.no_wrap": "no-wrap",

ui/frontend/src/lib/i18n/locales/ru.ts

@@ -129,7 +129,7 @@ const ru: Record<keyof typeof en, string> = {
 	"game.map.toggles.uninhabited_planets": "необитаемые планеты",
 	"game.map.toggles.unidentified_planets": "неопознанные планеты",
 	"game.map.toggles.unreachable_planets": "показывать недостижимые планеты",
-	"game.map.toggles.visibility_fog": "туман видимости",
+	"game.map.toggles.visible_hyperspace": "видимое гиперпространство",
 	"game.map.toggles.wrap.label": "перенос карты",
 	"game.map.toggles.wrap.torus": "тор",
 	"game.map.toggles.wrap.no_wrap": "без переноса",