simplify to pure reference doc, injection is platform responsibility

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

game-sdk.js

@@ -1,54 +1,9 @@
 /**
  * Game Platform SDK
  *
- * When running inside the platform, window.GameSDK is injected automatically
- * before your bundle loads. Use it directly:
+ * window.GameSDK is injected by the platform before your bundle loads.
  *
- *   const result = await GameSDK.submit(score)
- *   // result: { ok: true, rank: 3 } or { ok: false, error: '...' }
- *
- *   const name = GameSDK.getPlayerName()  // the current player's display name
- *   const id   = GameSDK.gameId           // this game's id string
- *
- * For local development (outside the platform), load this file as a script
- * tag before your bundle and call GameSDK.init(gameId, apiBase):
- *
- *   <script src="game-sdk.js"></script>
- *   <script>GameSDK.init('my-game', 'http://localhost:4006')</script>
- *   <script src="my-game.bundle.js"></script>
+ * GameSDK.gameId            — string, this game's id
+ * GameSDK.getPlayerName()   — string, current player's display name
+ * GameSDK.submit(score)     — Promise<{ ok: true, rank: number } | { ok: false, error: string }>
  */
-
-;(function () {
-  if (window.GameSDK && window.GameSDK._platform) return // already injected by platform
-
-  const NAME_KEY = 'gameName'
-
-  window.GameSDK = {
-    gameId: null,
-    _apiBase: '',
-
-    init: function (gameId, apiBase) {
-      this.gameId = gameId
-      this._apiBase = apiBase || ''
-    },
-
-    getPlayerName: function () {
-      return localStorage.getItem(NAME_KEY) || 'anonymous'
-    },
-
-    submit: async function (score) {
-      if (!this.gameId) return { ok: false, error: 'GameSDK not initialised — call GameSDK.init(gameId)' }
-      const name = this.getPlayerName()
-      try {
-        const r = await fetch(`${this._apiBase}/api/games/${this.gameId}/scores`, {
-          method: 'POST',
-          headers: { 'Content-Type': 'application/json' },
-          body: JSON.stringify({ name, score }),
-        })
-        return await r.json()
-      } catch {
-        return { ok: false, error: 'Network error' }
-      }
-    },
-  }
-})()