🤖 fix: update example scripts to use stdout/stderr semantics

Updated .cmux/scripts/demo and .cmux/scripts/echo to use:
- stdout for agent-visible output
- stderr for user-only progress messages

_Generated with mux_

Change-Id: Ibdcc0844cfd41715605b67498c6311c4a76db660
Signed-off-by: Thomas Kosiewski <tk@coder.com>

Author: ThomasK33

.cmux/scripts/demo

@@ -2,27 +2,20 @@
 # Description: Demo script to showcase the script execution feature. Accepts no arguments.
 set -euo pipefail
 
-# Regular output goes to stdout (visible in console logs)
-echo "Running demo script..."
-echo "Current workspace: $(pwd)"
-echo "Timestamp: $(date)"
+# Progress messages to stderr (shown to user, not sent to agent)
+echo "Running demo script..." >&2
+echo "Current workspace: $(pwd)" >&2
+echo "Timestamp: $(date)" >&2
 
-# Write formatted output to MUX_OUTPUT for toast display
-cat >>"$MUX_OUTPUT" <<'EOF'
+# Structured output to stdout (sent to agent)
+cat <<'EOF'
 ## 🎉 Script Execution Demo
 
 ✅ Script executed successfully!
 
-**Environment Variables Available:**
-- `MUX_OUTPUT`: Custom toast display
-- `MUX_PROMPT`: Send messages to agent
-EOF
-
-# Write a prompt to MUX_PROMPT to send a message to the agent
-cat >>"$MUX_PROMPT" <<'EOF'
-The demo script has completed successfully. The script execution feature is working correctly with:
-1. Custom toast output via MUX_OUTPUT
-2. Agent prompting via MUX_PROMPT
+**Output Semantics:**
+- `stdout`: Sent to the agent as tool result
+- `stderr`: Shown to user only (progress/debug info)
 
-You can now create workspace-specific scripts to automate tasks and interact with the agent.
+The demo script completed. You can create workspace-specific scripts to automate tasks.
 EOF

.cmux/scripts/echo

@@ -4,7 +4,7 @@ set -euo pipefail
 
 # Check if arguments were provided
 if [ $# -eq 0 ]; then
-  cat >>"$MUX_OUTPUT" <<'EOF'
+  cat <<'EOF'
 ## ⚠️ No Arguments Provided
 
 Usage: `/s echo <message...>`
@@ -14,10 +14,8 @@ EOF
   exit 0
 fi
 
-# Access arguments using standard bash positional parameters
-# $1 = first arg, $2 = second arg, $@ = all args, $# = number of args
-
-cat >>"$MUX_OUTPUT" <<EOF
+# Structured output to stdout (sent to agent)
+cat <<EOF
 ## 🔊 Echo Script
 
 **You said:** $@
@@ -31,18 +29,7 @@ cat >>"$MUX_OUTPUT" <<EOF
 **Individual arguments:**
 EOF
 
-
-# Echo arguments to stdout for AI tool visibility
-echo "Echoing arguments to stdout: $@"
-
 # Loop through each argument
 for i in $(seq 1 $#); do
-  echo "- Arg $i: ${!i}" >>"$MUX_OUTPUT"
+  echo "- Arg $i: ${!i}"
 done
-
-# Optionally send a message to the agent
-if [ $# -gt 3 ]; then
-  cat >>"$MUX_PROMPT" <<EOF
-The user passed more than 3 arguments to the echo script. They seem to be testing the argument passing feature extensively!
-EOF
-fi