refactor(context-window-recovery): split executor and storage into focused modules

Extract recovery strategies and storage management:
- recovery-strategy.ts, aggressive-truncation-strategy.ts
- summarize-retry-strategy.ts, target-token-truncation.ts
- empty-content-recovery.ts, message-builder.ts
- tool-result-storage.ts, storage-paths.ts, state.ts
- client.ts, tool-part-types.ts

src/hooks/anthropic-context-window-limit-recovery/target-token-truncation.ts

@@ -0,0 +1,85 @@
+import type { AggressiveTruncateResult } from "./tool-part-types"
+import { findToolResultsBySize, truncateToolResult } from "./tool-result-storage"
+
+function calculateTargetBytesToRemove(
+	currentTokens: number,
+	maxTokens: number,
+	targetRatio: number,
+	charsPerToken: number
+): { tokensToReduce: number; targetBytesToRemove: number } {
+	const targetTokens = Math.floor(maxTokens * targetRatio)
+	const tokensToReduce = currentTokens - targetTokens
+	const targetBytesToRemove = tokensToReduce * charsPerToken
+	return { tokensToReduce, targetBytesToRemove }
+}
+
+export function truncateUntilTargetTokens(
+	sessionID: string,
+	currentTokens: number,
+	maxTokens: number,
+	targetRatio: number = 0.8,
+	charsPerToken: number = 4
+): AggressiveTruncateResult {
+	const { tokensToReduce, targetBytesToRemove } = calculateTargetBytesToRemove(
+		currentTokens,
+		maxTokens,
+		targetRatio,
+		charsPerToken
+	)
+
+	if (tokensToReduce <= 0) {
+		return {
+			success: true,
+			sufficient: true,
+			truncatedCount: 0,
+			totalBytesRemoved: 0,
+			targetBytesToRemove: 0,
+			truncatedTools: [],
+		}
+	}
+
+	const results = findToolResultsBySize(sessionID)
+
+	if (results.length === 0) {
+		return {
+			success: false,
+			sufficient: false,
+			truncatedCount: 0,
+			totalBytesRemoved: 0,
+			targetBytesToRemove,
+			truncatedTools: [],
+		}
+	}
+
+	let totalRemoved = 0
+	let truncatedCount = 0
+	const truncatedTools: Array<{ toolName: string; originalSize: number }> = []
+
+	for (const result of results) {
+		const truncateResult = truncateToolResult(result.partPath)
+		if (truncateResult.success) {
+			truncatedCount++
+			const removedSize = truncateResult.originalSize ?? result.outputSize
+			totalRemoved += removedSize
+			truncatedTools.push({
+				toolName: truncateResult.toolName ?? result.toolName,
+				originalSize: removedSize,
+			})
+
+			if (totalRemoved >= targetBytesToRemove) {
+				break
+			}
+		}
+	}
+
+	const sufficient = totalRemoved >= targetBytesToRemove
+
+	return {
+		success: truncatedCount > 0,
+		sufficient,
+		truncatedCount,
+		totalBytesRemoved: totalRemoved,
+		targetBytesToRemove,
+		truncatedTools,
+	}
+}