merge: resolve CHANGELOG conflict with main, bump to v0.13.6.0

Main landed v0.13.5.0 (Factory Droid Compatibility) while this branch
already had v0.13.5.0 (GStack Learns). Bumped to v0.13.6.0 and kept
both entries in chronological order.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

bin/gstack-platform-detect

@@ -0,0 +1,20 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# gstack-platform-detect: show which AI coding agents are installed and gstack status
+printf "%-16s %-10s %-40s %s\n" "Agent" "Version" "Skill Path" "gstack"
+printf "%-16s %-10s %-40s %s\n" "-----" "-------" "----------" "------"
+for entry in "claude:claude" "codex:codex" "droid:factory" "kiro-cli:kiro"; do
+  bin="${entry%%:*}"; label="${entry##*:}"
+  if command -v "$bin" >/dev/null 2>&1; then
+    ver=$("$bin" --version 2>/dev/null | head -1 || echo "unknown")
+    case "$label" in
+      claude)  spath="$HOME/.claude/skills/gstack" ;;
+      codex)   spath="$HOME/.codex/skills/gstack" ;;
+      factory) spath="$HOME/.factory/skills/gstack" ;;
+      kiro)    spath="$HOME/.kiro/skills/gstack" ;;
+    esac
+    status=$([ -d "$spath" ] && echo "INSTALLED" || echo "NOT INSTALLED")
+    printf "%-16s %-10s %-40s %s\n" "$label" "$ver" "$spath" "$status"
+  fi
+done

bin/gstack-uninstall

@@ -10,6 +10,7 @@
 #   ~/.claude/skills/gstack       — global Claude skill install (git clone or vendored)
 #   ~/.claude/skills/{skill}      — per-skill symlinks created by setup
 #   ~/.codex/skills/gstack*       — Codex skill install + per-skill symlinks
+#   ~/.factory/skills/gstack*     — Factory Droid skill install + per-skill symlinks
 #   ~/.kiro/skills/gstack*        — Kiro skill install + per-skill symlinks
 #   ~/.gstack/                    — global state (config, analytics, sessions, projects,
 #                                   repos, installation-id, browse error logs)
@@ -63,6 +64,7 @@ if [ "$FORCE" -eq 0 ]; then
   echo "This will remove gstack from your system:"
   { [ -d "$HOME/.claude/skills/gstack" ] || [ -L "$HOME/.claude/skills/gstack" ]; } && echo "  ~/.claude/skills/gstack (+ per-skill symlinks)"
   [ -d "$HOME/.codex/skills" ] && echo "  ~/.codex/skills/gstack*"
+  [ -d "$HOME/.factory/skills" ] && echo "  ~/.factory/skills/gstack*"
   [ -d "$HOME/.kiro/skills" ] && echo "  ~/.kiro/skills/gstack*"
   [ "$KEEP_STATE" -eq 0 ] && [ -d "$STATE_DIR" ] && echo "  $STATE_DIR"
 
@@ -169,6 +171,16 @@ if [ -d "$CODEX_SKILLS" ]; then
   done
 fi
 
+# ─── Remove Factory Droid skills ────────────────────────────
+FACTORY_SKILLS="$HOME/.factory/skills"
+if [ -d "$FACTORY_SKILLS" ]; then
+  for _ITEM in "$FACTORY_SKILLS"/gstack*; do
+    [ -e "$_ITEM" ] || [ -L "$_ITEM" ] || continue
+    rm -rf "$_ITEM"
+    REMOVED+=("factory/$(basename "$_ITEM")")
+  done
+fi
+
 # ─── Remove Kiro skills ─────────────────────────────────────
 KIRO_SKILLS="$HOME/.kiro/skills"
 if [ -d "$KIRO_SKILLS" ]; then
@@ -191,6 +203,18 @@ if [ -n "$_GIT_ROOT" ] && [ -d "$_GIT_ROOT/.agents/skills" ]; then
   rmdir "$_GIT_ROOT/.agents" 2>/dev/null || true
 fi
 
+# ─── Remove per-project .factory/ sidecar ────────────────────
+if [ -n "$_GIT_ROOT" ] && [ -d "$_GIT_ROOT/.factory/skills" ]; then
+  for _ITEM in "$_GIT_ROOT/.factory/skills"/gstack*; do
+    [ -e "$_ITEM" ] || [ -L "$_ITEM" ] || continue
+    rm -rf "$_ITEM"
+    REMOVED+=("factory/$(basename "$_ITEM")")
+  done
+
+  rmdir "$_GIT_ROOT/.factory/skills" 2>/dev/null || true
+  rmdir "$_GIT_ROOT/.factory" 2>/dev/null || true
+fi
+
 # ─── Remove per-project state ───────────────────────────────
 if [ -n "$_GIT_ROOT" ]; then
   if [ -d "$_GIT_ROOT/.gstack" ]; then