ui/phase-20: ship-group inspector actions

Eight ship-group operations land on the inspector behind a single
inline-form panel: split, send, load, unload, modernize, dismantle,
transfer, join fleet. Each action either appends a typed command to
the local order draft or surfaces a tooltip explaining the
disabled state. Partial-ship operations emit an implicit
breakShipGroup command before the targeted action so the engine
sees a clean (Break, Action) pair on the wire.

`pkg/calc.BlockUpgradeCost` migrates from
`game/internal/controller/ship_group_upgrade.go` so the calc
bridge can wrap a pure pkg/calc formula; the controller now
imports it. The bridge surfaces the function as
`core.blockUpgradeCost`, which the inspector calls once per ship
block to render the modernize cost preview.

`GameReport.otherRaces` is decoded from the report's player block
(non-extinct, ≠ self) and feeds the transfer-to-race picker. The
planet inspector's stationed-ship rows become clickable for own
groups so the actions panel is reachable from the standard click
flow (the renderer continues to hide on-planet groups).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

pkg/calc/ship_test.go

@@ -0,0 +1,34 @@
+package calc_test
+
+import (
+	"math"
+	"testing"
+
+	"galaxy/calc"
+)
+
+func TestBlockUpgradeCost(t *testing.T) {
+	cases := []struct {
+		name        string
+		blockMass   float64
+		currentTech float64
+		targetTech  float64
+		want        float64
+	}{
+		{"zero block mass returns zero", 0, 1.0, 2.0, 0},
+		{"target equal to current returns zero", 5, 2.0, 2.0, 0},
+		{"target below current returns zero", 5, 2.0, 1.0, 0},
+		{"doubling tech on mass 5 costs 25", 5, 1.0, 2.0, 25},
+		{"doubling tech on mass 10 costs 50", 10, 1.0, 2.0, 50},
+		{"partial step from 2.0 to 2.5 on mass 5", 5, 2.0, 2.5, 10},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			got := calc.BlockUpgradeCost(tc.blockMass, tc.currentTech, tc.targetTech)
+			if math.Abs(got-tc.want) > 1e-9 {
+				t.Errorf("BlockUpgradeCost(%v, %v, %v) = %v, want %v",
+					tc.blockMass, tc.currentTech, tc.targetTech, got, tc.want)
+			}
+		})
+	}
+}