Remove stale play standalone file: README and INSTALL point to the title-screen download

INSTALL.md

@@ -2,8 +2,9 @@
 
 > *Technical matters, master. Crookfinger does not understand half of it, but the imps say it works.*
 
-**Just want to play?** Download [`play/DungeonCraft.html`](play/DungeonCraft.html) and open it in a browser -
-no server, no installation, no login. Savegames are downloaded as `.dcsave` files and loaded again with
+**Just want to play?** Open <https://dungeon.familie-zink.org/> in a browser. On the title screen, logged-in
+players can use *Download Standalone* to save `DungeonCraft.html`: the whole game in one file, without login and
+without server. Savegames from the standalone version are downloaded as `.dcsave` files and loaded again with
 *Load Game* (or dropped onto the game window).
 
 Everything below is for running your own server (with user accounts and savegames on the server),
@@ -136,7 +137,6 @@ number by one (a new month starts again at `00001`) and prints the old and the n
 
 | File | How |
 |---|---|
-| `play/DungeonCraft.html` | build the WASM file, then `python3 tools/make_standalone.py <www dir with dungeoncraft.wasm and mq_js_bundle.js> play/DungeonCraft.html` (the Docker image builds the same file under `/standalone/`) |
 | `docs/img/units`, `docs/img/icons` | `cargo test --release export_doc_images -- --ignored` |
 | `BESTIARY.md` | `python3 tools/make_bestiary.py` |
 | `VERSION` | `python3 tools/bump_version.py` - with every change to the game |