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/tests/game-shell-header.test.ts

@@ -138,10 +138,6 @@ describe("game-shell header", () => {
 			["view-menu-item-report", "/games/g1/report"],
 			["view-menu-item-battle", "/games/g1/battle"],
 			["view-menu-item-mail", "/games/g1/mail"],
-			[
-				"view-menu-item-designer-ship-class",
-				"/games/g1/designer/ship-class",
-			],
 			[
 				"view-menu-item-designer-science",
 				"/games/g1/designer/science",