feat(runtime): script-driven reflex daemon + Ink TUI dashboard

Pure-Pi runtime had three failure modes in practice:
  - slow: 20-60s per decision because LLM was in the hot path
  - expensive: every tick (defend, eat, idle) paid for a reasoning pass
  - invisible: required tmux capture-pane to know what the bot was doing

New runtime/ layer is a long-running Node daemon that owns the MC
connection, ticks a priority-ordered reflex chain (defend > eat > sleep
> idle) with NO LLM in the hot path, and exposes status + commands over
a Unix-socket IPC. tui/ is an Ink dashboard that attaches over IPC and
can detach freely — multiple TUI clients can connect at once.

Pi/Codex are still available, but as on-demand escalation: TUI hotkey
'a' spawns `pi -p "<prompt>"` as a subprocess and streams stdout into
the dashboard. The self-improvement loop (proposals → operator approval
→ Pi-driven patch → hot reload) is documented in docs/runtime.md but
not yet wired.

Reflex bodies are stubs today — they log decisions but don't drive
Mineflayer actions yet. The priority chain, IPC contract, and TUI are
fully working; subsequent commits will fill in defend/eat/sleep bodies
and wire automatic escalation.

Run with `npm run bot` + `npm run tui`. Pi-only fallback stays at
`npm run agent`.

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

runtime/reflex.js

@@ -0,0 +1,76 @@
+// Reflex layer: priority-ordered list of pure-script behaviors. Each reflex
+// inspects the latest snapshot and either returns a no-op or starts an action.
+// LLM is NOT called here. If every reflex declines, the tick yields and we try
+// again next interval. Escalation to Pi happens elsewhere, only when the bot
+// has been idle/stuck for an extended window.
+
+import { info, warn } from "./log.js";
+
+const REFLEX_LOG = "reflex";
+
+// A reflex returns one of:
+//   { action: "noop" }                       — nothing to do
+//   { action: "starting", kind, detail }     — kicked off async work
+//   { action: "completed", kind, detail }    — fully sync, already done
+// Reflexes must NEVER throw — they should log and return noop on failure.
+
+function defendReflex(ctx) {
+	const s = ctx.snapshot;
+	if (!s.connected) return { action: "noop" };
+	if (!s.closestHostile) return { action: "noop" };
+	if (s.closestHostile.distance > 6) return { action: "noop" };
+	// Stub: just log. Real attack/flee logic comes in a follow-up commit.
+	info(REFLEX_LOG, `defend: hostile ${s.closestHostile.name} at ${s.closestHostile.distance}m (stub, no action yet)`);
+	return { action: "completed", kind: "defend-stub", detail: s.closestHostile };
+}
+
+function eatReflex(ctx) {
+	const s = ctx.snapshot;
+	if (!s.connected) return { action: "noop" };
+	if (s.food === undefined || s.food >= 16) return { action: "noop" };
+	// Stub: log only. consume() integration arrives with the actions module.
+	info(REFLEX_LOG, `eat: hunger ${s.food}/20 (stub, no action yet)`);
+	return { action: "completed", kind: "eat-stub", detail: { food: s.food } };
+}
+
+function sleepReflex(ctx) {
+	const s = ctx.snapshot;
+	if (!s.connected) return { action: "noop" };
+	if (s.isDay) return { action: "noop" };
+	if (!s.inventory?.["red_bed"] && !s.inventory?.["white_bed"]) return { action: "noop" };
+	info(REFLEX_LOG, `sleep: night detected, bed in inventory (stub)`);
+	return { action: "completed", kind: "sleep-stub" };
+}
+
+function idleReflex(ctx) {
+	const s = ctx.snapshot;
+	if (!s.connected) return { action: "noop" };
+	// Once every ~10 ticks, log a heartbeat with HP/food/pos. Tunable later.
+	ctx.idleCounter = (ctx.idleCounter ?? 0) + 1;
+	if (ctx.idleCounter % 10 !== 0) return { action: "noop" };
+	info(REFLEX_LOG, `idle: hp=${s.health} food=${s.food} pos=${s.position?.x},${s.position?.y},${s.position?.z}`);
+	return { action: "completed", kind: "idle-heartbeat" };
+}
+
+const REFLEXES = [
+	{ name: "defend", fn: defendReflex },
+	{ name: "eat", fn: eatReflex },
+	{ name: "sleep", fn: sleepReflex },
+	{ name: "idle", fn: idleReflex },
+];
+
+export function runTick(ctx) {
+	for (const reflex of REFLEXES) {
+		let outcome;
+		try {
+			outcome = reflex.fn(ctx);
+		} catch (e) {
+			warn(REFLEX_LOG, `reflex ${reflex.name} threw: ${e?.message ?? e}`);
+			continue;
+		}
+		if (!outcome || outcome.action === "noop") continue;
+		// First non-noop wins — stop the chain so we don't double-act per tick.
+		return { reflex: reflex.name, ...outcome };
+	}
+	return null;
+}