feat(server): modifier profile protocol schemas + error codes

Adds wire schemas and error codes for the modifier-profile feature:

- ModifierProfileSchema mirrored in server/protocol.ts (server pins a different zod major, so the chess-side schema cannot be re-exported directly). A keyof parity check guards against drift.

- RoomCreatePayloadSchema gains an optional 'profile' field — additive, existing callers unaffected.

- modifier-profile.update (client->server) payload schema with roomCode, newProfile, and version (for optimistic-concurrency checks).

- modifier-profile.updated (server->client) broadcast payload interface, typed for future promotion to the discriminated union when the broadcast is wired through rooms.

- Four new error codes: MODIFIER_PROFILE_INVALID / NO_KING / INVULN_KING / DEADLOCK, exported as const literals alongside the enum.

- Client wire types (packages/chess/src/net/types.ts) mirror all of the above: ModifierProfileWire shape, optional 'profile' on Room{Create,Created,Joined} payloads, and the new modifier-profile.* client/server message envelopes.

- PROTOCOL.md documents the new request/response flow and extends the error-code table.

Tests: 20 new cases across ModifierProfileSchema, RoomCreate profile integration, ModifierProfileUpdatePayloadSchema, and error-code acceptance.

packages/chess/src/index.ts

@@ -60,3 +60,16 @@ export {
   type LayoutValidationResult,
 } from "./layouts/index.js";
 export { validateLayout } from "./layouts/validate.js";
+
+// Piece modifier profiles — orthogonal to layouts and presets. Exposed
+// so the server can type-check wire payloads against the authoritative
+// chess-side shape. The zod schema itself is NOT re-exported here
+// because the server package pins a different zod major; the server
+// mirrors the schema locally (same shape) for wire validation.
+export type {
+  ModifierProfile,
+  TypeModifier,
+  InstanceModifier,
+  ModifierKindId,
+  Direction,
+} from "./modifiers/types.js";

packages/chess/src/net/types.ts

@@ -28,7 +28,12 @@ export type ErrorCode =
   | "MSG_TOO_LARGE"
   | "BAD_TOKEN"
   | "INVALID_MESSAGE"
-  | "LAYOUT_INVALID";
+  | "LAYOUT_INVALID"
+  // Modifier-profile rejections — mirrored from server/protocol.ts.
+  | "MODIFIER_PROFILE_INVALID"
+  | "MODIFIER_PROFILE_NO_KING"
+  | "MODIFIER_PROFILE_INVULN_KING"
+  | "MODIFIER_PROFILE_DEADLOCK";
 
 // ---------------------------------------------------------------------------
 // Starting layout wire shapes (mirrors server/src/protocol.ts)
@@ -66,6 +71,50 @@ export interface Fact {
   value: unknown;
 }
 
+// ---------------------------------------------------------------------------
+// Modifier profile wire shapes (mirrors server/src/protocol.ts)
+// ---------------------------------------------------------------------------
+
+export type ModifierKindIdWire =
+  | "hp-bonus"
+  | "range-bonus"
+  | "direction-additions"
+  | "capture-flags"
+  | "promotion-override"
+  | "damage-resistance";
+
+export interface TypeModifierWire {
+  kind: ModifierKindIdWire;
+  pieceType: PieceType;
+  color: Color | "both";
+  value: unknown;
+}
+
+export interface InstanceModifierWire {
+  kind: ModifierKindIdWire;
+  /** Algebraic notation, e.g. "b1". */
+  square: string;
+  value: unknown;
+}
+
+/**
+ * JSON-serializable shape of a ModifierProfile as it travels on the
+ * wire. Mirrors the chess-package `ModifierProfile` type structurally;
+ * kept as an independent interface here so the net-types layer doesn't
+ * need to import from the modifiers subsystem (and accidentally pull
+ * in the descriptor registry side-effects).
+ */
+export interface ModifierProfileWire {
+  id: string;
+  name: string;
+  description: string;
+  layoutId?: string;
+  perType: TypeModifierWire[];
+  perInstance: InstanceModifierWire[];
+  version: 1;
+  source: "premade" | "custom";
+}
+
 // ---------------------------------------------------------------------------
 // Server → Client payloads
 // ---------------------------------------------------------------------------
@@ -124,6 +173,9 @@ export interface RoomCreatedPayload {
   /** Resolved starting layout. Optional on the wire for backward
    *  compat with pre-layouts servers. */
   layout?: ResolvedLayoutWire;
+  /** Modifier profile active at room creation. Optional for backward
+   *  compat with pre-modifiers servers. */
+  profile?: ModifierProfileWire;
 }
 
 export interface RoomJoinedPayload {
@@ -133,6 +185,21 @@ export interface RoomJoinedPayload {
   activeRules: string[];
   /** Resolved starting layout (see RoomCreatedPayload.layout). */
   layout?: ResolvedLayoutWire;
+  /** Active modifier profile when this client joined (see
+   *  RoomCreatedPayload.profile). */
+  profile?: ModifierProfileWire;
+}
+
+/**
+ * Server → client broadcast: the room's active modifier profile was
+ * replaced. Clients apply this to their local engine at the next turn
+ * boundary — the server guarantees the broadcast is ordered
+ * immediately before the ensuing `game.state` / `game.delta`.
+ */
+export interface ModifierProfileUpdatedPayload {
+  profile: ModifierProfileWire;
+  version: number;
+  appliedAt: "turn-boundary";
 }
 
 export interface ErrorPayload {
@@ -150,6 +217,21 @@ export interface RoomCreatePayload {
   /** Optional starting-layout selector. When omitted the server
    *  opens the room with the FIDE classic layout. */
   layout?: LayoutRequest;
+  /** Optional inline modifier profile applied at room creation. */
+  profile?: ModifierProfileWire;
+}
+
+/**
+ * Client → server intent: swap the active modifier profile for the
+ * room. Server validates and applies at the next turn boundary, then
+ * broadcasts `modifier-profile.updated` to both players. `version` is
+ * the profile version the client last observed; stale requests are
+ * rejected with `MODIFIER_PROFILE_INVALID`.
+ */
+export interface ModifierProfileUpdatePayload {
+  roomCode: string;
+  newProfile: ModifierProfileWire;
+  version: number;
 }
 
 export interface RoomJoinPayload {
@@ -182,6 +264,7 @@ export type ServerMessage =
   | MessageEnvelope<"game.presets", GamePresetsPayload>
   | MessageEnvelope<"room.created", RoomCreatedPayload>
   | MessageEnvelope<"room.joined", RoomJoinedPayload>
+  | MessageEnvelope<"modifier-profile.updated", ModifierProfileUpdatedPayload>
   | MessageEnvelope<"error", ErrorPayload>;
 
 export type ClientMessage =
@@ -189,4 +272,5 @@ export type ClientMessage =
   | MessageEnvelope<"room.join", RoomJoinPayload>
   | MessageEnvelope<"room.leave", Record<string, never>>
   | MessageEnvelope<"game.move", GameMovePayload>
-  | MessageEnvelope<"room.setPresets", RoomSetPresetsPayload>;
+  | MessageEnvelope<"room.setPresets", RoomSetPresetsPayload>
+  | MessageEnvelope<"modifier-profile.update", ModifierProfileUpdatePayload>;