feat(ui): Phase 30 ship-class calculator with goal-seek and reach circles

Fuse the standalone ship-class designer (Phases 17/18) into a sidebar calculator: live mass/speed/attack/defence/bombing results, a planet build-rate readout, single-target goal-seek, a modernization-cost mode, and auto reach circles on the map for the selected planet.

pkg/calc becomes the single source for the new math (no mirroring): extract BombingPower from the engine model and the per-turn ship-production loop from controller.ProduceShip into pkg/calc (engine now delegates), and add inverse goal-seek solvers in pkg/calc/solve.go. Thin-bridge the combat, planet-build, and solver functions through ui/core/calc + ui/wasm and rebuild core.wasm.

Remove the standalone designer view/route; the ship-classes table and the view/bottom menus open the calculator via a shared request store.

Docs: rewrite ui/PLAN.md Phase 30, adjust Phase 34 (realistic forecast + CAP/COL ownership), add ui/docs/calculator-ux.md, extend calc-bridge.md, fix navigation.md; remove ui/CALCULATOR.md.

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

ui/frontend/src/routes/games/[id]/+layout.svelte

@@ -61,6 +61,7 @@ fresh.
 		SelectionStore,
 		SELECTION_CONTEXT_KEY,
 	} from "$lib/selection.svelte";
+	import { calculatorLoadRequest } from "$lib/calculator/load-request.svelte";
 	import {
 		createRenderedReportSource,
 		RENDERED_REPORT_CONTEXT_KEY,
@@ -226,6 +227,17 @@ fresh.
 		sidebarOpen = true;
 	});
 
+	// Reveal the calculator whenever the ship-classes table or the
+	// bottom-tabs entry asks to load a class (or start a fresh design).
+	let lastCalcLoadToken = 0;
+	$effect(() => {
+		const token = calculatorLoadRequest.token;
+		if (token === lastCalcLoadToken) return;
+		lastCalcLoadToken = token;
+		activeTab = "calculator";
+		sidebarOpen = true;
+	});
+
 	function toggleSidebar(): void {
 		sidebarOpen = !sidebarOpen;
 	}

ui/frontend/src/routes/games/[id]/designer/ship-class/[[classId]]/+page.svelte

@@ -1,5 +0,0 @@
-<script lang="ts">
-	import DesignerShipClass from "$lib/active-view/designer-ship-class.svelte";
-</script>
-
-<DesignerShipClass />