feat(send): ✨ add slash-command mode for precise input control

Co-Authored-By: Lilith Autocommit <noreply@atlilith.com>

bin/rclaude

@@ -808,8 +808,31 @@ cmd_list() {
 #   rclaude send --match <pat> -- <text...>
 #   rclaude send ... --yes -- <text...>     # actually send (default: preview)
 #   rclaude send ... --dry-run -- <text...> # explicit preview (overrides --yes)
+#   rclaude send ... --slash -- /foo bar    # slash-command mode (see below)
+#
+# Input-buffer contract (important — read before debugging missing sends):
+#
+# Delivery uses `tmux send-keys -l` followed by `Enter`. tmux types into
+# whatever buffer is currently focused in the target pane — it has no notion
+# of "Claude prompt-ready". Two consequences:
+#
+#   1. If Claude is mid-turn or already has buffered text in its input area
+#      (queued user input, a partial draft), the new text is APPENDED. The
+#      single Enter submits the merged blob as ONE user message. To stop
+#      that, every send first clears the input line (`C-a C-k`) before
+#      typing the payload.
+#
+#   2. Slash commands like `/remote-control claire-plum` only fire when they
+#      are the ENTIRE user message (leading `/`, no surrounding text). Use
+#      `--slash` to enforce this: the text must begin with `/`, must not
+#      contain newlines, and the line-clear is mandatory. Without --slash,
+#      a leading `/` is just text — easy to accidentally turn a slash
+#      command into prose.
+#
+# Concurrent sends to the same pane can still race the input buffer. Callers
+# that need ordering should serialize externally (flock on a per-pane lock).
 cmd_send() {
-    _sel=""; _pat=""; _dry=0; _yes=0
+    _sel=""; _pat=""; _dry=0; _yes=0; _slash=0
     while [ $# -gt 0 ]; do
         case $1 in
             --all)      [ -n "$_sel" ] && { echo "rclaude send: only one selector allowed" >&2; exit 2; }
@@ -824,6 +847,7 @@ cmd_send() {
                         _sel=match; _pat=${1#--match=}; shift ;;
             --dry-run)  _dry=1; shift ;;
             --yes)      _yes=1; shift ;;
+            --slash)    _slash=1; shift ;;
             --)         shift; break ;;
             -*)         echo "rclaude send: unknown flag: $1" >&2; exit 2 ;;
             *)          break ;;
@@ -832,12 +856,16 @@ cmd_send() {
 
     if [ -z "$_sel" ]; then
         cat >&2 <<'EOF'
-usage: rclaude send (--all | --host <h> | --match <pat>) [--dry-run] [--yes] -- <text...>
+usage: rclaude send (--all | --host <h> | --match <pat>) [--dry-run] [--yes] [--slash] -- <text...>
   --all          target every live claude-* tmux session on scan_hosts
   --host <h>     target every claude-* session on a specific host
   --match <pat>  substring match against tmux session name (which embeds slug)
   --dry-run      preview targets and exit (default unless --yes is passed)
   --yes          actually deliver (still prints preview first)
+  --slash        slash-command mode: text must start with '/', no newlines;
+                 the input line is force-cleared before the payload so the
+                 command lands solo (any buffered text is discarded). Use
+                 this for /remote-control, /clear, etc.
 EOF
         exit 2
     fi
@@ -848,6 +876,17 @@ EOF
         exit 2
     fi
 
+    if [ "$_slash" = 1 ]; then
+        case $_text in
+            /*) ;;
+            *)  echo "rclaude send --slash: text must start with '/' (got: $_text)" >&2; exit 2 ;;
+        esac
+        case $_text in
+            *"$(printf '\n')"*)
+                echo "rclaude send --slash: text must not contain newlines" >&2; exit 2 ;;
+        esac
+    fi
+
     # Gather candidate rows across all hosts, then filter.
     _rows=$(scan_hosts | while IFS= read -r _h; do list_tmux_on "$_h"; done \
             | filter_targets "$_sel" "$_pat")