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

.claude-plugin/plugin.json

@@ -1,7 +1,7 @@
 {
   "name": "agent-loop",
   "version": "0.8.0",
-  "description": "Autonomous generator-evaluator agent loop for long-running coding tasks. Plan with /agent-loop:init, then execute with /agent-loop:run.",
+  "description": "Autonomous generator-evaluator agent loop for long-running coding tasks. Run /agent-loop:run to start.",
   "author": {
     "name": "Sheldon"
   },