Remove misleading production-style checkpoint aliases

These two files are paper ablation checkpoints, not production-ready Zatom-2 releases. They remain available under explicit Table 1 and Table 3 ablation filenames.

zatom2_latest.ckpt

@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:a47edf3608c30bcb4c9273b7a71bc81b0ef7a282d6c0aa4a741463176c8590c8
-size 2251811845

zatom2_s_latest.ckpt

@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:7a08a2df01b1d1a2176586a231aa0e0a19c707ee1c6be673ea35d2dda4a08ab5
-size 1182248327