feat(v0.4.0): finish vNext plan — anti-loop, skill-graph, worldDelta diff, flee→motion

Completes the remaining v0.4.0 plan items and one fix motivated by a live
in-game observation (flee hanging 30s against a persistent zombie).

- flee → MotionService.gotoSafe: structured {stuck|timeout|nopath} in ~4s with
  a blind-retreat fallback, instead of the observed 30s pathfinder hang + 3
  watchdog replans. Movements setup guarded so it is unit-testable.
- QW5 anti-loop (runtime/anti-loop.js): same skill failing >=3x in 5min →
  30min blacklist (reflex shouldSkip) + one-shot improvement_request
  (bot.js drainFired -> writeProposal).
- 4.1 closed-loop worldDelta: runSkill snapshots inventory before execute and
  attaches the real delta (_invObserved) to every successful result; opt-in
  skill.expectGain asserts the claimed gain or returns world_unchanged.
- 3.6 skill-graph (Plan4MC): declarative requires/produces for ~20 skills;
  prerequisitesMet/canRun/runnableFrontier; GoalManager annotates suggestions
  with blockedBy when prereqs are unmet.

+22 tests (472 total green). Live smoke confirmed dig-in works and no new
errors; flee loop is what this commit's flee migration addresses.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

runtime/reflex.js

@@ -712,6 +712,14 @@ function curriculumReflex(ctx) {
 		}
 	}
 
+	// QW5 anti-loop: this skill failed ≥3× in 5 min → it's blacklisted. Skip
+	// and nudge toward exploration so we leave the situation that loops it.
+	if (ctx.antiLoop?.shouldSkip(skillId)) {
+		ctx.skillBackoff = ctx.skillBackoff ?? {};
+		ctx.skillBackoff["__wander_hint__"] = Date.now() + SKILL_BACKOFF_MS;
+		return { action: "noop", kind: "anti-loop-blacklisted", label: skillId };
+	}
+
 	// v0.2.0 — consult learned lessons. If a high-confidence lesson says
 	// "avoid <skillId> in this situation", swap to its preferred
 	// alternative (or back off entirely if no safe alternative is named).
@@ -734,6 +742,9 @@ function curriculumReflex(ctx) {
 	ctx.dispatch(() => runSkill(dispatchSkillId, ctx, dispatchArgs), dispatchSkillId, {
 		onComplete: (res) => {
 			ctx.skillBackoff = ctx.skillBackoff ?? {};
+			// QW5 anti-loop bookkeeping: feed every outcome so repeated failures
+			// of the same skill get detected, blacklisted and ticketed.
+			ctx.antiLoop?.record({ skillId: dispatchSkillId, ok: !!res?.ok, code: res?.code ?? null });
 			if (advice.lessonId) reportAdviceOutcome({ lessonId: advice.lessonId, succeeded: !!res?.ok });
 			if (appliedRecommendationId) {
 				markRecommendationOutcome(appliedRecommendationId, {