refactor: harden session store updates

Co-authored-by: Tyler Yust <tyler6204@users.noreply.github.com>

src/config/sessions/store.ts

@@ -45,9 +45,16 @@ export function clearSessionStoreCacheForTest(): void {
   SESSION_STORE_CACHE.clear();
 }
 
-export function loadSessionStore(storePath: string): Record<string, SessionEntry> {
+type LoadSessionStoreOptions = {
+  skipCache?: boolean;
+};
+
+export function loadSessionStore(
+  storePath: string,
+  opts: LoadSessionStoreOptions = {},
+): Record<string, SessionEntry> {
   // Check cache first if enabled
-  if (isSessionStoreCacheEnabled()) {
+  if (!opts.skipCache && isSessionStoreCacheEnabled()) {
     const cached = SESSION_STORE_CACHE.get(storePath);
     if (cached && isSessionStoreCacheValid(cached)) {
       const currentMtimeMs = getFileMtimeMs(storePath);
@@ -88,7 +95,7 @@ export function loadSessionStore(storePath: string): Record<string, SessionEntry
   }
 
   // Cache the result if caching is enabled
-  if (isSessionStoreCacheEnabled()) {
+  if (!opts.skipCache && isSessionStoreCacheEnabled()) {
     SESSION_STORE_CACHE.set(storePath, {
       store: structuredClone(store), // Store a copy to prevent external mutations
       loadedAt: Date.now(),
@@ -168,6 +175,19 @@ export async function saveSessionStore(
   });
 }
 
+export async function updateSessionStore<T>(
+  storePath: string,
+  mutator: (store: Record<string, SessionEntry>) => Promise<T> | T,
+): Promise<T> {
+  return await withSessionStoreLock(storePath, async () => {
+    // Always re-read inside the lock to avoid clobbering concurrent writers.
+    const store = loadSessionStore(storePath, { skipCache: true });
+    const result = await mutator(store);
+    await saveSessionStoreUnlocked(storePath, store);
+    return result;
+  });
+}
+
 type SessionStoreLockOptions = {
   timeoutMs?: number;
   pollIntervalMs?: number;