[playersettings] fix delete setting

apps/playersettings/README.md

@@ -10,11 +10,18 @@ Player-settings worker served on the `playersettings` subdomain.
   `key=…&value=…` (or a JSON `{key,value}` / array) and **upserts** it into the
   player's settings, keyed by the `sub` claim of the Bearer JWT. Returns `200`.
   Persisted in Workers KV (`RECFLARE_PLAYER_SETTINGS`, key `player:<id>`).
+- `DELETE /playersettings` — `[Authorize]`. Removes a setting from the player's
+  map. The client sends a bare form-urlencoded `key=PlayerShoppingBagId` (no
+  `value`); a JSON body and a `?key=` query param are also read. Deleting a key
+  that isn't stored is a no-op `200`, not a `404`.
 
 > A full settings PUT would replace the player's _entire_ settings set on each
 > call; we merge instead, so a single-key PUT (e.g. `key=PlayerSessionCount`)
 > doesn't wipe the others.
 
+> Emptying the map with DELETE puts the player back to a first read: the next
+> `GET` re-seeds the defaults.
+
 ## KV namespace
 
 ```sh