began sleep.c, worked sleep_crypto.c, sleep_tree.c

renamed sleep.3 for conflicting
added mock visual for client extra/datthang.png
direction: need to save keys, save seckey ~/.datt/secret_keys
.datt datt with extra t decided for testing until port complete

docs/dat.sleep.3

@@ -0,0 +1,16 @@
+.TH SLEEP 3 "September 2025" "Dat-Thang LTS" "Libary Functions Manual"
+.SH NAME
+
+.SH SYNOPSIS
+.nf
+.B #include <sleep.h>
+
+.SH DESCRIPTION
+
+.SH RETURN VALUES
+
+.SH FILES
+
+.SH AUTHORS
+
+.SH NOTES