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/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",