ui/phase-16: pick any planet in reach + stronger pick-mode dim

The cargo-route picker filtered out unidentified planets, so an
early-game player who had spotted but not surveyed a destination
could not configure a route to it — the engine has no such
restriction (`game/internal/controller/route.go.PlanetRouteSet`
only checks ownership of the origin and `util.ShortDistance(...) <=
FligthDistance`). Drop the unidentified guard and document the
contract in `cargo-routes-ux.md` plus a comment over `reachableSet()`.

Pick-mode dim now drops both alpha and tint on out-of-reach
planets so bright shapes (`STYLE_LOCAL` is `0x6dd2ff`) collapse
into a single muted gray. The single-channel `dimAlpha=0.3` was too
gentle against the dark theme — the user reported the dim wasn't
visible. Tighten to `dimAlpha=0.35 + dimTint=0x303841`; restore
both on tear-down.

Also threads through the user's `pkg/calc/race.go.FligthDistance`
addition: `calc-bridge.md` records the new Go-side reference (the
engine's `Race.FlightDistance()` already wraps it), and the picker
comment points at the canonical formula location.

Tests:
- `inspector-planet-cargo-routes.test.ts` adds two cases — a
  reach-spans-every-kind case (own + foreign + uninhabited +
  unidentified all picked when in range) and a successful pick to
  an unidentified destination.
- All 356 vitest cases + chromium-desktop / webkit-desktop e2e
  cargo-routes pass.

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

ui/frontend/src/map/render.ts

@@ -380,6 +380,7 @@ export async function createRenderer(opts: RendererOptions): Promise<RendererHan
 	let pickOptions: PickModeOptions | null = null;
 	let pickOverlay: Graphics | null = null;
 	const dimmedAlphaBackup = new Map<Graphics, number>();
+	const dimmedTintBackup = new Map<Graphics, number>();
 	const detachPickListeners: Array<() => void> = [];
 
 	const handleViewportClicked = (e: {
@@ -462,6 +463,8 @@ export async function createRenderer(opts: RendererOptions): Promise<RendererHan
 		detachPickListeners.length = 0;
 		for (const [g, alpha] of dimmedAlphaBackup) g.alpha = alpha;
 		dimmedAlphaBackup.clear();
+		for (const [g, tint] of dimmedTintBackup) g.tint = tint;
+		dimmedTintBackup.clear();
 		if (pickOverlay !== null) {
 			pickOverlay.destroy();
 			pickOverlay = null;
@@ -484,7 +487,9 @@ export async function createRenderer(opts: RendererOptions): Promise<RendererHan
 			if (options.reachableIds.has(id)) continue;
 			for (const g of list) {
 				dimmedAlphaBackup.set(g, g.alpha);
+				dimmedTintBackup.set(g, g.tint as number);
 				g.alpha = PICK_OVERLAY_STYLE.dimAlpha;
+				g.tint = PICK_OVERLAY_STYLE.dimTint;
 			}
 		}
 		// Overlay graphic. Lives in the origin copy so the central