chore(v0.4.1): open branch — disable auto-improve self-patcher by default

Carry the uncommitted off-switch into v0.4.1 and bump version to 0.4.1.

- runtime/auto-improve.js: PEPA_AUTO_IMPROVE=off skips the self-patcher,
  which committed LLM diffs and checked out branches (observed 2026-05-28
  checking out a stale local `main`). Direction is operator-drained
  improvement_requests, not auto-apply — proposals still written to disk.
- package.json: 0.4.0 -> 0.4.1

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "pepa-pi-bot",
-  "version": "0.4.0",
+  "version": "0.4.1",
   "private": true,
   "description": "An autonomous, self-extending Minecraft player powered by Pi and Mineflayer.",
   "license": "MIT",