Use conservative four-token MTP drafts

tests/frank_large_config.bats

@@ -33,7 +33,7 @@ TEMPLATE_FILE="$REPO_ROOT/scripts/chat-template.jinja"
     grep -qF -- '--spec-draft-n-max "$MTP_N_MAX"' "$SERVE_FILE"
     grep -qF -- '--spec-draft-p-min "$MTP_P_MIN"' "$SERVE_FILE"
     # qualified profile tunables are exposed in the env
-    grep -q '^MTP_N_MAX=16$' "$ENV_FILE"
+    grep -q '^MTP_N_MAX=4$' "$ENV_FILE"
     grep -q '^MTP_P_MIN=0.60$' "$ENV_FILE"
     grep -q '^SPEC_MTP_STRICT_QWEN=on$' "$ENV_FILE"
     grep -q '^MTP_BACKEND_SAMPLING=on$' "$ENV_FILE"