fix: prevent agent from suggesting non-existent /gsd:transition command (#1081) (#1129)

The agent was telling users to run '/gsd:transition' after phase completion,
but this command does not exist. transition.md is an internal workflow invoked
by execute-phase during auto-advance.

Changes:
- Add <internal_workflow> banner to transition.md declaring it is NOT a user command
- Add explicit warning in execute-phase completion section that /gsd:transition
  does not exist
- Add 'only suggest commands listed above' guard to prevent hallucination
- Update resume-project.md to avoid ambiguous 'Transition' label
- Replace 'ready for transition' with 'ready for next step' in execute-plan.md

Fixes #1081

.release-monitor.sh

@@ -0,0 +1,51 @@
+#!/usr/bin/env bash
+# Release monitor for gsd-build/get-shit-done
+# Checks every 15 minutes, writes new release info to a signal file
+
+REPO="gsd-build/get-shit-done"
+SIGNAL_FILE="/tmp/gsd-new-release.json"
+STATE_FILE="/tmp/gsd-monitor-last-tag"
+LOG_FILE="/tmp/gsd-monitor.log"
+
+# Initialize with current latest
+echo "v1.25.1" > "$STATE_FILE"
+rm -f "$SIGNAL_FILE"
+
+log() {
+  echo "[$(date '+%Y-%m-%d %H:%M:%S')] $1" >> "$LOG_FILE"
+  echo "[$(date '+%Y-%m-%d %H:%M:%S')] $1"
+}
+
+log "Monitor started. Watching $REPO for releases newer than v1.25.1"
+log "Checking every 15 minutes..."
+
+while true; do
+  sleep 900  # 15 minutes
+
+  LAST_KNOWN=$(cat "$STATE_FILE" 2>/dev/null)
+  
+  # Get latest release tag
+  LATEST=$(gh release list -R "$REPO" --limit 1 2>/dev/null | awk '{print $1}')
+  
+  if [ -z "$LATEST" ]; then
+    log "WARNING: Failed to fetch releases (network issue?)"
+    continue
+  fi
+
+  if [ "$LATEST" != "$LAST_KNOWN" ]; then
+    log "NEW RELEASE DETECTED: $LATEST (was: $LAST_KNOWN)"
+    
+    # Fetch release notes
+    RELEASE_BODY=$(gh release view "$LATEST" -R "$REPO" --json tagName,name,body 2>/dev/null)
+    
+    # Write signal file for the agent to pick up
+    echo "$RELEASE_BODY" > "$SIGNAL_FILE"
+    echo "$LATEST" > "$STATE_FILE"
+    
+    log "Signal file written to $SIGNAL_FILE"
+    # Exit so the agent can process it, then restart
+    exit 0
+  else
+    log "No new release. Latest is still $LATEST"
+  fi
+done