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/tests/inspector-planet-cargo-routes.test.ts

@@ -221,6 +221,100 @@ describe("planet inspector — cargo routes", () => {
 		).toBeInTheDocument();
 	});
 
+	test("the reachable set spans every planet kind in range, not only own", async () => {
+		// Reach = 40 * 1.5 = 60. Each candidate at distance 50 — in
+		// reach. The picker must include the foreign-race planet,
+		// the uninhabited rock, and the unidentified target so the
+		// engine's "destinations may be any planet" rule is honoured
+		// (route.go: only the source's ownership is enforced).
+		const { ui, pick } = mount(
+			makePlanet({
+				number: 1,
+				name: "Earth",
+				x: 100,
+				y: 100,
+				kind: "local",
+			}),
+			[
+				makePlanet({
+					number: 1,
+					name: "Earth",
+					x: 100,
+					y: 100,
+					kind: "local",
+				}),
+				makePlanet({
+					number: 2,
+					name: "Alpha",
+					x: 150,
+					y: 100,
+					kind: "other",
+					owner: "Aliens",
+				}),
+				makePlanet({
+					number: 3,
+					name: "Rock",
+					x: 100,
+					y: 150,
+					kind: "uninhabited",
+				}),
+				makePlanet({
+					number: 4,
+					name: "",
+					x: 50,
+					y: 100,
+					kind: "unidentified",
+				}),
+			],
+			[],
+			1.5,
+		);
+		await fireEvent.click(ui.getByTestId("inspector-planet-cargo-slot-col-add"));
+		await waitFor(() => expect(pick.invocations.length).toBe(1));
+		expect(
+			Array.from(pick.invocations[0]!.request.reachableIds).sort(),
+		).toEqual([2, 3, 4]);
+	});
+
+	test("the picker accepts an unidentified destination", async () => {
+		const { ui, pick } = mount(
+			makePlanet({
+				number: 1,
+				name: "Earth",
+				x: 100,
+				y: 100,
+				kind: "local",
+			}),
+			[
+				makePlanet({
+					number: 1,
+					name: "Earth",
+					x: 100,
+					y: 100,
+					kind: "local",
+				}),
+				makePlanet({
+					number: 9,
+					name: "",
+					x: 130,
+					y: 100,
+					kind: "unidentified",
+				}),
+			],
+			[],
+			1.5,
+		);
+		await fireEvent.click(ui.getByTestId("inspector-planet-cargo-slot-mat-add"));
+		await waitFor(() => expect(pick.invocations.length).toBe(1));
+		pick.invocations[0]!.resolve(9);
+		await waitFor(() => expect(draft.commands).toHaveLength(1));
+		const cmd = draft.commands[0]!;
+		expect(cmd.kind).toBe("setCargoRoute");
+		if (cmd.kind !== "setCargoRoute") return;
+		expect(cmd.destinationPlanetNumber).toBe(9);
+		expect(cmd.loadType).toBe("MAT");
+	});
+
 	test("a successful pick emits setCargoRoute and closes the prompt", async () => {
 		const { ui, pick } = mount(
 			makePlanet({ number: 1, name: "Earth", x: 100, y: 100 }),