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>

docs/FUNCTIONAL.md

@@ -802,11 +802,13 @@ every change applies within one frame (no Pixi remount):
   off, hides every non-LOCAL planet that sits beyond
   `FlightDistance(localPlayerDrive)` of every LOCAL planet
   (torus-aware metric).
-- **View** — visibility fog toggle (slightly lighter overlay
-  outside the union of `VisibilityDistance(localPlayerDrive)`
-  circles around LOCAL planets; LOCAL planets are always
-  exempt) plus the torus / no-wrap radio that switches the
-  renderer mode while preserving the camera centre.
+- **View** — "visible hyperspace" toggle (slightly lighter
+  overlay outside the union of
+  `VisibilityDistance(localPlayerDrive)` circles around LOCAL
+  planets; LOCAL planets are always exempt — the toggle is
+  named after the visible part of the map rather than the
+  obscured one) plus the torus / no-wrap radio that switches
+  the renderer mode while preserving the camera centre.
 
 LOCAL planets are always rendered — they have no toggle. Every
 other toggle defaults to ON. Hiding a planet cascades onto every

docs/FUNCTIONAL_ru.md

@@ -823,10 +823,11 @@ Directory-промоушен ([Раздел 5](#5-реестр-названий-
   не-LOCAL планету, отстоящую дальше
   `FlightDistance(localPlayerDrive)` от любой LOCAL-планеты
   (метрика учитывает торическую развёртку).
-- **Вид** — переключатель тумана видимости (чуть более светлая
-  заливка вне объединения окружностей
+- **Вид** — переключатель «видимое гиперпространство» (чуть
+  более светлая заливка вне объединения окружностей
   `VisibilityDistance(localPlayerDrive)` вокруг LOCAL-планет;
-  LOCAL-планеты всегда вне фильтра) плюс радиогруппа
+  LOCAL-планеты всегда вне фильтра — тоггл назван по видимой
+  области карты, а не по затемнённой) плюс радиогруппа
   «торус / без переноса», переключающая режим рендерера с
   сохранением центра камеры.