fix: remove 'as any' type casts in retention feature

- Import and use RetentionSetting type instead of 'as any' in extension.ts
- Use proper type narrowing for metadata parsing instead of 'as any'

src/extension.ts

@@ -44,7 +44,7 @@ import {
 } from "./activate"
 import { initializeI18n } from "./i18n"
 import { flushModels, initializeModelCacheRefresh, refreshModels } from "./api/providers/fetchers/modelCache"
-import { purgeOldTasks } from "./utils/task-history-retention"
+import { purgeOldTasks, RetentionSetting } from "./utils/task-history-retention"
 
 /**
  * Built using https://github.com/microsoft/vscode-webview-ui-toolkit
@@ -175,7 +175,7 @@ export async function activate(context: vscode.ExtensionContext) {
 		outputChannel.appendLine(`[Retention] Startup purge: setting=${retention}`)
 
 		const result = await purgeOldTasks(
-			retention as any,
+			retention as RetentionSetting,
 			contextProxy.globalStorageUri.fsPath,
 			(m) => {
 				outputChannel.appendLine(m)

src/utils/task-history-retention.ts

@@ -153,8 +153,10 @@ export async function purgeOldTasks(
 		// First try to get a timestamp from task_metadata.json (if present)
 		try {
 			const raw = await fs.readFile(metadataPath, "utf8")
-			const meta = JSON.parse(raw)
-			const maybeTs = Number((meta as any)?.ts)
+			const meta: unknown = JSON.parse(raw)
+			const maybeTs = Number(
+				typeof meta === "object" && meta !== null && "ts" in meta ? (meta as { ts: unknown }).ts : undefined,
+			)
 			if (Number.isFinite(maybeTs)) {
 				ts = maybeTs
 			}