refactor(src): split oversized modules

src/agents/pi-embedded-runner/session-manager-cache.ts

@@ -0,0 +1,60 @@
+import { Buffer } from "node:buffer";
+import fs from "node:fs/promises";
+
+import { isCacheEnabled, resolveCacheTtlMs } from "../../config/cache-utils.js";
+
+type SessionManagerCacheEntry = {
+  sessionFile: string;
+  loadedAt: number;
+};
+
+const SESSION_MANAGER_CACHE = new Map<string, SessionManagerCacheEntry>();
+const DEFAULT_SESSION_MANAGER_TTL_MS = 45_000; // 45 seconds
+
+function getSessionManagerTtl(): number {
+  return resolveCacheTtlMs({
+    envValue: process.env.CLAWDBOT_SESSION_MANAGER_CACHE_TTL_MS,
+    defaultTtlMs: DEFAULT_SESSION_MANAGER_TTL_MS,
+  });
+}
+
+function isSessionManagerCacheEnabled(): boolean {
+  return isCacheEnabled(getSessionManagerTtl());
+}
+
+export function trackSessionManagerAccess(sessionFile: string): void {
+  if (!isSessionManagerCacheEnabled()) return;
+  const now = Date.now();
+  SESSION_MANAGER_CACHE.set(sessionFile, {
+    sessionFile,
+    loadedAt: now,
+  });
+}
+
+function isSessionManagerCached(sessionFile: string): boolean {
+  if (!isSessionManagerCacheEnabled()) return false;
+  const entry = SESSION_MANAGER_CACHE.get(sessionFile);
+  if (!entry) return false;
+  const now = Date.now();
+  const ttl = getSessionManagerTtl();
+  return now - entry.loadedAt <= ttl;
+}
+
+export async function prewarmSessionFile(sessionFile: string): Promise<void> {
+  if (!isSessionManagerCacheEnabled()) return;
+  if (isSessionManagerCached(sessionFile)) return;
+
+  try {
+    // Read a small chunk to encourage OS page cache warmup.
+    const handle = await fs.open(sessionFile, "r");
+    try {
+      const buffer = Buffer.alloc(4096);
+      await handle.read(buffer, 0, buffer.length, 0);
+    } finally {
+      await handle.close();
+    }
+    trackSessionManagerAccess(sessionFile);
+  } catch {
+    // File doesn't exist yet, SessionManager will create it
+  }
+}