refactor: clean up and rename binaries

config/shared/bin/test-true-color

@@ -0,0 +1,48 @@
+#!/usr/bin/env bash
+
+echo
+awk 'BEGIN{
+    s="/\\/\\/\\/\\/\\"; s=s s s s s s s s;
+    for (colnum = 0; colnum<77; colnum++) {
+        r = 255-(colnum*255/76);
+        g = (colnum*510/76);
+        b = (colnum*255/76);
+        if (g>255) g = 510-g;
+        printf "\033[48;2;%d;%d;%dm", r,g,b;
+        printf "\033[38;2;%d;%d;%dm", 255-r,255-g,255-b;
+        printf "%s\033[0m", substr(s,colnum+1,1);
+    }
+    printf "\n";
+}'
+
+# --- Environment diagnostics -------------------------------------------------
+echo
+echo "──────────────────────────────"
+echo " Environment and Tmux Details "
+echo "──────────────────────────────"
+echo "TERM: ${TERM}"
+echo "COLORTERM: ${COLORTERM:-undefined}"
+echo
+
+if command -v tmux >/dev/null && tmux info &>/dev/null; then
+  echo "Tmux RGB/Tc capabilities:"
+  tmux info | grep -E "RGB|Tc" || echo "(none found)"
+  echo
+  echo "Tmux server terminal options:"
+  tmux show-options -s | grep terminal || echo "(none found)"
+else
+  echo "Tmux not running or unavailable."
+fi
+
+# --- Underline capability test -----------------------------------------------
+echo
+echo "Underline styles test:"
+printf '\x1b[58:2::255:0:0m' # red underline color
+printf '\x1b[4:1msingle '    # single underline
+printf '\x1b[4:2mdouble '    # double underline
+printf '\x1b[4:3mcurly '     # curly underline
+printf '\x1b[4:4mdotted '    # dotted underline
+printf '\x1b[4:5mdashed '    # dashed underline
+printf '\x1b[0m\n'
+
+echo