fix: critical bugs, stale refs, README rewrite, security fixes

- Fix evaluator bypass on last story (moved completion check)
- Fix all stale command name references across README, loop.sh, skills, plugin.json
- Fix explore evaluator false rejects (.loop/ files are expected)
- Fix stderr capture order in headless mode
- Fix shell injection risk in hooks.sh python fallback
- Remove .DS_Store from tracking
- Rewrite README to match current architecture (single entry point, tmux, optional tools)
- Add XcodeBuildMCP and iOS simulator MCP to optional tools docs

setup.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 # Agent Loop — project setup script
 # Scaffolds .loop/ directory and generates config.json.
-# Called by /agent-loop:init or run directly.
+# Called by /agent-loop:setup or /agent-loop:run, or run directly.
 #
 # Usage:
 #   setup.sh <mode>           # mode: implement, explore, or fix
@@ -120,5 +120,5 @@ echo "[setup] Mode: $MODE"
 echo "[setup] Config: .loop/config.json"
 echo ""
 echo "Next steps (in Claude Code):"
-echo "  /agent-loop:plan    # Generate stories from your spec or description"
+echo "  /agent-loop:stories    # Generate stories from your spec or description"
 echo ""