fix(game): #59 — per-command rejection on PUT /api/v1/order

Validation of a player's order now applies every command against a
transient game-state snapshot and records the per-command outcome
(cmdApplied, cmdErrorCode) in each command's meta. The order is
persisted even when some commands are rejected, and the response is
202 + UserGamesOrder so clients can surface the partial failure
without the chain collapsing into "downstream service is unavailable".

Pkg/error consts are reshelved onto three explicit ranges with a
package doc and helpers (IsInternalCode/IsInputCode/IsGameStateCode):
1xxx internal/server (500/501), 2xxx structural input (400), 3xxx
game-state per-command rejection (400 when escaping HTTP, otherwise
recorded as cmdErrorCode). Two pre-existing typos fixed mechanically
(ErrBeakGroupNumberNotEnough -> ErrBreakGroupNumberNotEnough,
ErrRaceExinct -> ErrRaceExtinct) along with all callsites.

Engine errorResponse maps *GenericError by shelf rather than mapping
everything to 500. The Quit-not-last structural check in
Controller.ValidateOrder is preserved and its type assertion fixed
(was a value assertion against a pointer-typed command, so the check
silently never fired).

Backend, gateway and UI are unchanged — they were already correct on
the 202 path; only the engine collapsing per-command rejection into
500 was needed.

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

game/internal/controller/ship_class_test.go

@@ -31,7 +31,7 @@ func TestShipClassCreate(t *testing.T) {
 		e.GenericErrorText(e.ErrInputUnknownRace))
 	assert.ErrorContains(t,
 		g.ShipClassCreate(Race_Extinct.Name, "Drone", 1, 0, 0, 0, 0),
-		e.GenericErrorText(e.ErrRaceExinct))
+		e.GenericErrorText(e.ErrRaceExtinct))
 	assert.ErrorContains(t,
 		g.ShipClassCreate(Race_0.Name, BadEntityName, 1, 0, 0, 0, 0),
 		e.GenericErrorText(e.ErrInputEntityTypeNameInvalid))
@@ -109,7 +109,7 @@ func TestShipClassMerge(t *testing.T) {
 		e.GenericErrorText(e.ErrInputEntityNotExists))
 	assert.ErrorContains(t,
 		g.ShipClassMerge(Race_Extinct.Name, "Spy", "Drone"),
-		e.GenericErrorText(e.ErrRaceExinct))
+		e.GenericErrorText(e.ErrRaceExtinct))
 	assert.ErrorContains(t,
 		g.ShipClassMerge(Race_0.Name, "Spy", "Spy"),
 		e.GenericErrorText(e.ErrInputEntityTypeNameEquality))
@@ -134,7 +134,7 @@ func TestShipClassRemove(t *testing.T) {
 		e.GenericErrorText(e.ErrInputUnknownRace))
 	assert.ErrorContains(t,
 		g.ShipClassRemove(Race_Extinct.Name, Race_0_Freighter),
-		e.GenericErrorText(e.ErrRaceExinct))
+		e.GenericErrorText(e.ErrRaceExtinct))
 	assert.ErrorContains(t,
 		g.ShipClassRemove(Race_0.Name, "Elephant"),
 		e.GenericErrorText(e.ErrInputEntityNotExists))