adapter: re-save weights as fp16 (100 MB → ~50 MB)

adapter_model.safetensors

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:0e4ed4bb9531fd6cef0ede99f1c709843e1a6f54287c91892898cf1cf7cfaa5d
-size 100697728
+oid sha256:4aa180b398b6019d95e661f232dea73365ade1f74b68a3fc30732a282a85a52f
+size 50365992