feat: implement safe leave, profile reset, and full game reset semantics

docs/API_CONTRACT.md

@@ -38,7 +38,7 @@ Failure (maximum 160 encoded bytes):
 ```
 
 `code` is one of `MALFORMED_JSON`, `PAYLOAD_TOO_LARGE`, `INVALID_NAME`,
-`INVALID_ROLE`, `INVALID_MODE`, `INVALID_COORDINATE`, `UNAUTHORIZED`,
+`INVALID_ROLE`, `INVALID_MODE`, `INVALID_COORDINATE`, `UNAUTHORIZED`, `SESSION_INVALIDATED`,
 `NO_PLAYER_SLOT`, `NO_SPECTATOR_SLOT`, `FORBIDDEN_ROLE`, `WRONG_PHASE`,
 `NOT_YOUR_TURN`, `CELL_ALREADY_SHOT`, `STALE_GAME`, or `SERVER_BUSY`.
 `message` is Russian and at most 80 UTF-8 bytes.
@@ -51,11 +51,14 @@ Failure (maximum 160 encoded bytes):
 | `GET /api/health`          |    128 B target | diagnostics without secrets, 320 B; includes reset reason |
 | `POST /api/session/join`   |      192 B body | `{name,requestedRole}`; token and role, 192 B |
 | `POST /api/session/resume` |       96 B body | `{token}`; role and state metadata, 192 B     |
+| `POST /api/session/leave`  |       80 B body | `{token,gameId}`; releases only that session   |
+| `POST /api/session/profile-reset` | 80 B body | `{token,gameId}`; server release for local profile reset |
 | `POST /api/game/config`    |       96 B body | `{token,gameId,mode}`; common envelope        |
 | `POST /api/game/start`     |       80 B body | `{token,gameId}`; common envelope             |
 | `POST /api/game/shot`      |       96 B body | `{token,gameId,x,y}`; common envelope         |
 | `POST /api/game/rematch`   |       80 B body | `{token,gameId}`; common envelope             |
 | `POST /api/game/abort`     |       80 B body | `{token,gameId}`; common envelope             |
+| `POST /api/game/reset`     |       80 B body | `{token,gameId}`; player-only full RAM reset  |
 | `GET /api/state?version=N` |    128 B target | one role-safe state, 768 B                    |
 | `GET /api/statistics`      |    128 B target | role and bounded match/cumulative counters    |
 
@@ -63,6 +66,15 @@ The session token is in each POST body. For `GET /api/state`, it is supplied
 in `X-Session-Token`; absence creates a spectator-safe view. It is never a URL
 parameter.
 
+`leave` and `profile-reset` release only the requesting session; profile data is
+cleared by the browser in Milestone 022. A player leaving an active match aborts
+that match and returns remaining valid players to the lobby. `game/reset` is
+available only to an authenticated player and atomically invalidates every
+session, clears match and cumulative statistics, and starts a fresh game
+generation. Successful recovery responses contain `resetReason` (`session_left`,
+`profile_reset`, or `game_reset`) and `generation`. Invalidated-token state
+polling returns `SESSION_INVALIDATED` with the same bounded recovery metadata.
+
 ## Role-safe state event
 
 The HTTP state response and WebSocket `state` event use this single 768-byte

docs/MVP.md

@@ -274,10 +274,13 @@ struct Board {
 | `GET` | `/api/info` | Состояние устройства и доступность мест без скрытых данных |
 | `POST` | `/api/session/join` | Вход по имени и желаемой роли |
 | `POST` | `/api/session/resume` | Восстановление роли по токену |
+| `POST` | `/api/session/leave` | Освобождение только текущей сессии |
+| `POST` | `/api/session/profile-reset` | Освобождение сессии перед локальной очисткой профиля |
 | `POST` | `/api/game/config` | Выбор режима игроком 1 |
 | `POST` | `/api/game/start` | Запуск готовой партии |
 | `POST` | `/api/game/shot` | Выстрел по координатам |
 | `POST` | `/api/game/rematch` | Подтверждение повторной игры |
+| `POST` | `/api/game/reset` | Аварийный полный сброс игровой памяти игроком |
 | `GET` | `/api/state?version=N` | Снимок разрешённого состояния и резервный опрос |
 | `GET` | `/api/health` | Проверка доступности сервера |
 

docs/openapi.yaml

@@ -73,6 +73,24 @@ paths:
         '400': { $ref: '#/components/responses/BadRequest' }
         '401': { $ref: '#/components/responses/Unauthorized' }
         '413': { $ref: '#/components/responses/PayloadTooLarge' }
+  /api/session/leave:
+    post:
+      summary: Release only the authenticated session
+      requestBody:
+        required: true
+        content: { application/json: { schema: { $ref: '#/components/schemas/GameRequest' } } }
+      responses: &recoveryResponses
+        '200': { $ref: '#/components/responses/RecoveryAccepted' }
+        '400': { $ref: '#/components/responses/BadRequest' }
+        '409': { $ref: '#/components/responses/Conflict' }
+        '413': { $ref: '#/components/responses/PayloadTooLarge' }
+  /api/session/profile-reset:
+    post:
+      summary: Release the authenticated session for a browser-local profile reset
+      requestBody:
+        required: true
+        content: { application/json: { schema: { $ref: '#/components/schemas/GameRequest' } } }
+      responses: *recoveryResponses
   /api/game/config:
     post:
       summary: Set the game mode (Player 1, lobby only)
@@ -131,6 +149,18 @@ paths:
             schema:
               $ref: '#/components/schemas/GameRequest'
       responses: *commandResponses
+  /api/game/reset:
+    post:
+      summary: Player-only full in-memory game reset
+      requestBody:
+        required: true
+        content: { application/json: { schema: { $ref: '#/components/schemas/GameRequest' } } }
+      responses:
+        '200': { $ref: '#/components/responses/RecoveryAccepted' }
+        '400': { $ref: '#/components/responses/BadRequest' }
+        '403': { $ref: '#/components/responses/Forbidden' }
+        '409': { $ref: '#/components/responses/Conflict' }
+        '413': { $ref: '#/components/responses/PayloadTooLarge' }
   /api/state:
     get:
       summary: Get a complete role-safe state snapshot
@@ -175,6 +205,11 @@ components:
       schema: { $ref: '#/components/schemas/Token' }
       description: Omit only when a spectator-safe public view is intended.
   responses:
+    RecoveryAccepted:
+      description: Recovery completed or an idempotent retry observed the same completed recovery.
+      content:
+        application/json:
+          schema: { $ref: '#/components/schemas/RecoveryAccepted' }
     CommandAccepted:
       description: Command accepted by the authoritative application layer.
       content:
@@ -269,6 +304,13 @@ components:
         - type: object
           required: [role]
           properties: { role: { $ref: '#/components/schemas/Role' } }
+    RecoveryAccepted:
+      type: object
+      required: [ok, resetReason, generation]
+      properties:
+        ok: { type: boolean, enum: [true] }
+        resetReason: { type: string, enum: [session_left, profile_reset, game_reset] }
+        generation: { $ref: '#/components/schemas/GameId' }
     Info:
       type: object
       required: [ok, phase, gameId, version, player1Available, player2Available, player1Name, player2Name, spectatorsAvailable]