feat(runtime): persistent memory — world-journal + scenario-memory

Closes a structural gap: the bot now actually REMEMBERS what it
discovered and what it tried. Two stores live under state/<host>/ and
are wired in automatically.

runtime/world-journal.js
- Append-only JSONL of discovered points (chopped, placed, base,
  shelter, farm, dead_end). Indexed by 16-block spatial grid; O(neighbors)
  nearest() lookups; 6 h age prune; 10k line ceiling with trim.
- leanestQuadrant({x,z}) reports the quadrant the bot has the FEWEST
  markers in — used by explore.far to circle rather than retread.
- summary() exposed for the stuck-incident proposal body.

runtime/scenario-memory.js
- Sliding window of (skillId, situationHash, code, ok, detail) tuples.
- situationHash() is a coarse fingerprint (16x8x16 cell + day/night +
  food/hp bucket + inv key set + closest hostile). So "same kind of
  place + same kind of state" matches.
- shouldSkip({skillId, situation}) → true after ≥3 failures within 30
  min UNLESS a more-recent success in the same situation un-locks it.
- recentTailFor() exposed for the stuck-incident body.

Wiring (runtime/bot.js):
- dispatchAction captures situationHash BEFORE the action runs and
  records (skillId, situation, code, ok) after — failures are attributed
  to the dispatch-time state, not the partial-effect state.
- worldDelta fields (choppedAt, minedAt, placedAt, baseAt, shelterAt,
  plantedAt, harvestedAt, tilledAt) auto-flow into the journal.
- no_target + silent_dig_failure also write dead_end markers.

Scheduler / skills now consume memory:
- reflex.js curriculum reflex calls memory.shouldSkip — if the same
  (skill, situation) failed 3+ times recently, auto-converts to a
  wander hint so the bot leaves and tries elsewhere.
- explore.far calls journal.leanestQuadrant when multiple cardinal
  directions are walkable and prefers the less-explored one.
- gather.logs walks to the nearest known "chopped" bucket within 96
  blocks before falling through to findBlock — chunks with confirmed
  trees are more likely to yield another.

stuck-incident body now includes journal byKind + last 12 scenario
entries so Pi can write a structural fix, not just a guard clause.

Architecturally: this is the foundation for "bot rewrites itself".
The proposals Pi now receives carry real signal about what was tried
and what's around, instead of a single snapshot in isolation.

10 new tests (world-journal × 5, scenario-memory × 5). npm test 134/134.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

runtime/reflex.js

@@ -25,6 +25,7 @@ import {
 	wander,
 } from "./actions.js";
 import { runSkill, getSkill } from "./skills/index.js";
+import { situationHash } from "./scenario-memory.js";
 
 // Each "wander hint" triggered by a skill returning no_target should take
 // the bot meaningfully further than 16 blocks — otherwise the curriculum
@@ -226,6 +227,20 @@ function curriculumReflex(ctx) {
 	const backoffUntil = ctx.skillBackoff?.[skillId] ?? 0;
 	if (Date.now() < backoffUntil) return { action: "noop" };
 
+	// Scenario memory: this exact (skill, situation) pattern failed N times
+	// recently? Skip and let the wander/explore hint move us to a different
+	// situation. The hash includes coarse position + day/night + food + hp
+	// + inventory keys + nearby hostile — "same kind of place + state".
+	if (ctx.memory?.shouldSkip && ctx.snapshot) {
+		const sit = situationHash(ctx.snapshot);
+		if (ctx.memory.shouldSkip({ skillId, situation: sit })) {
+			// Pretend a wander hint fired so the next tick will explore.
+			ctx.skillBackoff = ctx.skillBackoff ?? {};
+			ctx.skillBackoff["__wander_hint__"] = Date.now() + SKILL_BACKOFF_MS;
+			return { action: "noop" };
+		}
+	}
+
 	ctx.lastCurriculumAt = Date.now();
 	ctx.dispatch(() => runSkill(skillId, ctx), skillId, {
 		onComplete: (res) => {