fix(ui-calculator): keep calculator state long-lived; don't eject on planet click

Move the calculator's inputs into a page-level calculatorState singleton so they survive the sidebar unmounting the tab on a tab switch (the inspector auto-opens on a planet click). ensureGame resets the design when the active game changes.

While on the calculator, a planet click no longer switches to the inspector — the calculator consumes the selection in its planet area / reach circles. Halve the reach-circle stroke width.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

ui/frontend/tests/calculator-tab.test.ts

@@ -7,10 +7,15 @@
 import "@testing-library/jest-dom/vitest";
 import "fake-indexeddb/auto";
 import { fireEvent, render } from "@testing-library/svelte";
-import { afterEach, beforeEach, describe, expect, test } from "vitest";
+import { afterEach, beforeEach, describe, expect, test, vi } from "vitest";
+
+// The calculator reads `page.params.id` to scope its long-lived state to
+// the active game; stub a stable id so the component test has a router.
+vi.mock("$app/state", () => ({ page: { params: { id: "calc-test-game" } } }));
 
 import { i18n } from "../src/lib/i18n/index.svelte";
 import CalculatorTab from "../src/lib/sidebar/calculator-tab.svelte";
+import { calculatorState } from "../src/lib/calculator/calc-state.svelte";
 import { CORE_CONTEXT_KEY, CoreHolder } from "../src/lib/core-context.svelte";
 import {
 	ORDER_DRAFT_CONTEXT_KEY,
@@ -106,6 +111,8 @@ beforeEach(async () => {
 	draft = new OrderDraftStore();
 	await draft.init({ cache: new IDBCache(db), gameId: GAME_ID });
 	i18n.resetForTests("en");
+	// The calculator state is a module singleton shared across cases.
+	calculatorState.reset();
 });
 
 afterEach(async () => {