refactor(ralph-loop): split hook into state controller and event handler modules

Extract Ralph loop lifecycle management:
- loop-state-controller.ts: start/stop/recovery state machine
- ralph-loop-event-handler.ts: event handling logic
- continuation-prompt-builder.ts, continuation-prompt-injector.ts
- completion-promise-detector.ts, loop-session-recovery.ts
- message-storage-directory.ts

src/hooks/ralph-loop/loop-session-recovery.ts

@@ -0,0 +1,33 @@
+type SessionState = {
+	isRecovering?: boolean
+}
+
+export function createLoopSessionRecovery(options?: { recoveryWindowMs?: number }) {
+	const recoveryWindowMs = options?.recoveryWindowMs ?? 5000
+	const sessions = new Map<string, SessionState>()
+
+	function getSessionState(sessionID: string): SessionState {
+		let state = sessions.get(sessionID)
+		if (!state) {
+			state = {}
+			sessions.set(sessionID, state)
+		}
+		return state
+	}
+
+	return {
+		isRecovering(sessionID: string): boolean {
+			return getSessionState(sessionID).isRecovering === true
+		},
+		markRecovering(sessionID: string): void {
+			const state = getSessionState(sessionID)
+			state.isRecovering = true
+			setTimeout(() => {
+				state.isRecovering = false
+			}, recoveryWindowMs)
+		},
+		clear(sessionID: string): void {
+			sessions.delete(sessionID)
+		},
+	}
+}