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/map/render.ts

@@ -704,31 +704,31 @@ export async function createRenderer(opts: RendererOptions): Promise<RendererHan
 		},
 		isPrimitiveHidden: (id) => hiddenIds.has(id),
 		setVisibilityFog: (circles) => {
-			if (circles.length === 0) {
-				for (const g of fogGraphics) {
-					g.parent?.removeChild(g);
-					g.destroy();
-				}
-				fogGraphics = [];
-				return;
-			}
-			// Recreate the fog Graphics on every call. Pixi v8's
-			// `Graphics.clear()` exists but reusing the same instance
-			// with multiple `.cut()` operations across calls can
-			// accumulate stale path state in our experience; a fresh
-			// Graphics keeps the contract simple.
+			// Drop the old fog Graphics first — every flip rebuilds
+			// from scratch instead of mutating in place, so the
+			// implementation stays simple and Pixi-v8-residue-free.
 			for (const g of fogGraphics) {
 				g.parent?.removeChild(g);
 				g.destroy();
 			}
 			fogGraphics = [];
+			if (circles.length === 0) return;
+			// Layered overpaint: a fog-tinted rectangle covers the
+			// world, then opaque background-coloured circles drawn on
+			// top reveal the visible-hyperspace area. The natural
+			// rendering order handles overlapping circles correctly —
+			// Pixi v8's `Graphics.cut()` produces inconsistent
+			// results for unions of holes (the previous Phase 29
+			// implementation hit this), and the overpaint approach
+			// avoids the geometry calculation entirely.
+			const bg = theme.background;
 			for (const copy of copies) {
 				const g = new Graphics();
 				g.rect(0, 0, opts.world.width, opts.world.height);
 				g.fill({ color: FOG_COLOR, alpha: 1 });
 				for (const c of circles) {
 					g.circle(c.x, c.y, c.radius);
-					g.cut();
+					g.fill({ color: bg, alpha: 1 });
 				}
 				// Fog sits below every primitive on the same copy so
 				// planet glyphs paint on top. `addChildAt(g, 0)` keeps