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

prompts/evaluator/explore.md

@@ -6,7 +6,7 @@ You are evaluating an analysis/exploration task. The generator claims to have an
 
 Before any other checks, verify explore mode's read-only constraint:
 1. Run `git diff {{PRE_GENERATOR_SHA}}..HEAD --name-only`
-2. If ANY file outside `.loop/triage/` was modified or committed, **REJECT immediately** — explore mode is read-only. The generator must not modify host project files.
+2. If ANY file outside `.loop/` was modified or committed, **REJECT immediately** — explore mode is read-only. The generator must not modify host project files. (Files inside `.loop/` like `prd.json` and `progress.md` are expected.)
 
 ## Exploration-Specific Checks