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/router/handler/handler.go

@@ -142,6 +142,18 @@ func stateResponse(s game.State) rest.StateResponse {
 	return *result
 }
 
+// errorResponse renders err onto c and reports whether the caller
+// should stop further processing. The HTTP status is selected by the
+// GenericError shelf (see pkg/error for the taxonomy):
+//
+//   - validator.ValidationErrors (request struct binding) → 400 with
+//     {"error": ...}.
+//   - GenericError, ErrGameNotInitialized → 501 with no body.
+//   - GenericError on the internal shelf (1xxx) → 500 with
+//     {"generic_error", "code"}.
+//   - GenericError on the input-validation shelf (2xxx) or the
+//     game-state shelf (3xxx) → 400 with {"generic_error", "code"}.
+//   - everything else (non-GenericError) → 500 with {"error": ...}.
 func errorResponse(c *gin.Context, err error) bool {
 	if err == nil {
 		return false
@@ -153,9 +165,11 @@ func errorResponse(c *gin.Context, err error) bool {
 	}
 
 	if ge, ok := errors.AsType[*e.GenericError](err); ok {
-		switch ge.Code {
-		case e.ErrGameNotInitialized:
+		switch {
+		case ge.Code == e.ErrGameNotInitialized:
 			c.Status(http.StatusNotImplemented)
+		case e.IsInputCode(ge.Code), e.IsGameStateCode(ge.Code):
+			c.JSON(http.StatusBadRequest, gin.H{"generic_error": ge.Error(), "code": ge.Code})
 		default:
 			c.JSON(http.StatusInternalServerError, gin.H{"generic_error": ge.Error(), "code": ge.Code})
 		}

game/internal/router/order_test.go

@@ -7,6 +7,7 @@ import (
 	"net/http/httptest"
 	"testing"
 
+	e "galaxy/error"
 	"galaxy/model/order"
 	"galaxy/model/rest"
 
@@ -1016,6 +1017,128 @@ func TestPutOrderEngineError(t *testing.T) {
 	assert.Equal(t, http.StatusInternalServerError, w.Code, w.Body)
 }
 
+// TestPutOrderPerCommandRejection — when the engine returns an order
+// where some commands carry `cmdErrorCode != 0`, the handler must
+// still answer 202 with the full UserGamesOrder body so the client
+// can surface the per-command failure (rather than treating the
+// response as a generic error).
+func TestPutOrderPerCommandRejection(t *testing.T) {
+	applied := true
+	rejectedFlag := false
+	rejectedCode := e.ErrInputEntityNotExists
+	zero := 0
+	result := &order.UserGamesOrder{
+		GameID:    uuid.New(),
+		UpdatedAt: 4242,
+		Commands: []order.DecodableCommand{
+			&order.CommandShipClassCreate{
+				CommandMeta: order.CommandMeta{
+					CmdID:      id(),
+					CmdType:    order.CommandTypeShipClassCreate,
+					CmdApplied: &applied,
+					CmdErrCode: &zero,
+				},
+				Name:  "Drone",
+				Drive: 1,
+			},
+			&order.CommandPlanetProduce{
+				CommandMeta: order.CommandMeta{
+					CmdID:      id(),
+					CmdType:    order.CommandTypePlanetProduce,
+					CmdApplied: &rejectedFlag,
+					CmdErrCode: &rejectedCode,
+				},
+				Number:     0,
+				Production: "SHIP",
+				Subject:    "Nonexistent",
+			},
+		},
+	}
+	executor := &dummyExecutor{ValidateOrderResult: result}
+	r := setupRouterExecutor(executor)
+
+	payload := &rest.Command{
+		Actor: commandDefaultActor,
+		Commands: []json.RawMessage{
+			encodeCommand(&order.CommandShipClassCreate{
+				CommandMeta: order.CommandMeta{CmdID: id(), CmdType: order.CommandTypeShipClassCreate},
+				Name:        "Drone",
+				Drive:       1,
+			}),
+			encodeCommand(&order.CommandPlanetProduce{
+				CommandMeta: order.CommandMeta{CmdID: id(), CmdType: order.CommandTypePlanetProduce},
+				Number:      0,
+				Production:  "SHIP",
+				Subject:     "Nonexistent",
+			}),
+		},
+	}
+
+	w := httptest.NewRecorder()
+	req, _ := http.NewRequest(apiCommandMethod, apiOrderPath, asBody(payload))
+	r.ServeHTTP(w, req)
+
+	require.Equal(t, http.StatusAccepted, w.Code, w.Body)
+
+	var got struct {
+		GameID    uuid.UUID         `json:"game_id"`
+		UpdatedAt int64             `json:"updatedAt"`
+		Commands  []json.RawMessage `json:"cmd"`
+	}
+	require.NoError(t, json.Unmarshal(w.Body.Bytes(), &got))
+	require.Len(t, got.Commands, 2)
+
+	var first struct {
+		CmdApplied *bool `json:"cmdApplied"`
+		CmdErrCode *int  `json:"cmdErrorCode"`
+	}
+	require.NoError(t, json.Unmarshal(got.Commands[0], &first))
+	require.NotNil(t, first.CmdApplied)
+	assert.True(t, *first.CmdApplied)
+
+	var second struct {
+		CmdApplied *bool `json:"cmdApplied"`
+		CmdErrCode *int  `json:"cmdErrorCode"`
+	}
+	require.NoError(t, json.Unmarshal(got.Commands[1], &second))
+	require.NotNil(t, second.CmdApplied)
+	assert.False(t, *second.CmdApplied)
+	require.NotNil(t, second.CmdErrCode)
+	assert.Equal(t, e.ErrInputEntityNotExists, *second.CmdErrCode)
+}
+
+// TestPutOrderStructuralRejection — order-level structural errors
+// (e.g. `quit` not the last command) come back from the executor as a
+// *GenericError on the input shelf, which must map to HTTP 400 with
+// the `{"generic_error","code"}` envelope rather than 500.
+func TestPutOrderStructuralRejection(t *testing.T) {
+	executor := &dummyExecutor{ValidateOrderErr: e.NewQuitCommandFollowedByCommandError()}
+	r := setupRouterExecutor(executor)
+
+	payload := &rest.Command{
+		Actor: commandDefaultActor,
+		Commands: []json.RawMessage{
+			encodeCommand(&order.CommandRaceQuit{
+				CommandMeta: order.CommandMeta{CmdID: id(), CmdType: order.CommandTypeRaceQuit},
+			}),
+		},
+	}
+
+	w := httptest.NewRecorder()
+	req, _ := http.NewRequest(apiCommandMethod, apiOrderPath, asBody(payload))
+	r.ServeHTTP(w, req)
+
+	require.Equal(t, http.StatusBadRequest, w.Code, w.Body)
+
+	var got struct {
+		Code int    `json:"code"`
+		Msg  string `json:"generic_error"`
+	}
+	require.NoError(t, json.Unmarshal(w.Body.Bytes(), &got))
+	assert.Equal(t, e.ErrInputQuitCommandFollowedByCommand, got.Code)
+	assert.NotEmpty(t, got.Msg)
+}
+
 func TestGetOrderQueryValidation(t *testing.T) {
 	for _, tc := range []struct {
 		description  string