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>

game/internal/controller/ship_group_upgrade_test.go

@@ -13,12 +13,6 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func TestBlockUpgradeCost(t *testing.T) {
-	assert.Equal(t, 00.0, controller.BlockUpgradeCost(1, 1.0, 1.0))
-	assert.Equal(t, 25.0, controller.BlockUpgradeCost(5, 1.0, 2.0))
-	assert.Equal(t, 50.0, controller.BlockUpgradeCost(10, 1.0, 2.0))
-}
-
 func TestGroupUpgradeCost(t *testing.T) {
 	sg := &g.ShipGroup{
 		Tech: map[g.Tech]g.Float{