chore(sleep): English-only across the engine, plugins, and docs

Remove every non-ASCII/CJK character for a professional open-source repo:
  - harvest.py: drop hardcoded Chinese feedback phrases; add an env-based
    extensibility hook (SKILLOPT_SLEEP_NEG_FEEDBACK / _POS_FEEDBACK) so any
    locale can be added without baking one in. Verified with a German example.
  - rollout.py / consolidate.py: English comments.
  - README.md section heading + anchor, CONTROLLABLE_DREAMING.md, plugin.json,
    marketplace.json (also fixed stale path skillopt-sleep-plugin ->
    plugins/claude-code), SKILL.md: English only.
  - Remove the internal WAKE_UP_SUMMARY.md note (not user-facing, not referenced).

Verified: zero CJK chars remain anywhere; 29 tests pass.

Co-Authored-By: Claude Opus 4 <noreply@anthropic.com>

skillopt_sleep/consolidate.py

@@ -126,7 +126,7 @@ def consolidate(
     if evolve_skill:
         if rollouts_k > 1:
             # multi-rollout contrastive reflection: run each train task K times
-            # and distill a rule from the good-vs-bad contrast (the "脑补" signal).
+            # and distill a rule from the good-vs-bad contrast (the imagination signal).
             from skillopt_sleep.rollout import multi_rollout, contrastive_reflect
             sets = [multi_rollout(backend, t, cand_skill, cand_memory, k=rollouts_k)
                     for t in train_tasks]