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>

pkg/calc/ship_test.go

@@ -32,3 +32,27 @@ func TestBlockUpgradeCost(t *testing.T) {
 		})
 	}
 }
+
+func TestBombingPower(t *testing.T) {
+	cases := []struct {
+		name                                   string
+		weapons, weaponsTech, armament, number float64
+		want                                   float64
+	}{
+		// Parity with the engine's Battle_Station fixture
+		// (game/internal/model/game/group_test.go): (sqrt(30)/10+1)*30*3.
+		{"battle station, single ship", 30, 1, 3, 1, 139.29503},
+		{"battle station, two ships scale linearly", 30, 1, 3, 2, 278.59006},
+		{"no armament: zero power", 30, 1, 0, 5, 0},
+		{"no weapons: zero power", 0, 1, 3, 5, 0},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			got := calc.BombingPower(tc.weapons, tc.weaponsTech, tc.armament, tc.number)
+			if math.Abs(got-tc.want) > 1e-3 {
+				t.Errorf("BombingPower(%v, %v, %v, %v) = %v, want %v",
+					tc.weapons, tc.weaponsTech, tc.armament, tc.number, got, tc.want)
+			}
+		})
+	}
+}