refactor: split prompt async gate modules

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/shared/prompt-async-gate/reservations.ts

@@ -0,0 +1,95 @@
+import { log } from "../logger"
+import type { PromptAsyncReservation, PromptAsyncReservationReleaseOptions } from "./types"
+
+const promptAsyncReservations = new Map<string, PromptAsyncReservation>()
+let expiredReservationHandler: ((sessionID: string) => void) | undefined
+
+export function setExpiredReservationHandler(handler: (sessionID: string) => void): void {
+  expiredReservationHandler = handler
+}
+
+function notifyExpiredReservation(sessionID: string): void {
+  expiredReservationHandler?.(sessionID)
+}
+
+function pruneExpiredReservations(now = Date.now()): void {
+  const expiredSessionIDs: string[] = []
+  for (const [sessionID, reservation] of promptAsyncReservations) {
+    if (typeof reservation.expiresAt === "number" && reservation.expiresAt <= now) {
+      promptAsyncReservations.delete(sessionID)
+      expiredSessionIDs.push(sessionID)
+      log("[prompt-async-gate] expired reservation released", {
+        sessionID,
+        source: reservation.source,
+      })
+    }
+  }
+  for (const sessionID of expiredSessionIDs) {
+    notifyExpiredReservation(sessionID)
+  }
+}
+
+export function getActiveReservation(sessionID: string): PromptAsyncReservation | undefined {
+  pruneExpiredReservations()
+  return promptAsyncReservations.get(sessionID)
+}
+
+export function getPromptReservation(sessionID: string): PromptAsyncReservation | undefined {
+  return promptAsyncReservations.get(sessionID)
+}
+
+export function setPromptReservation(sessionID: string, reservation: PromptAsyncReservation): void {
+  promptAsyncReservations.set(sessionID, reservation)
+}
+
+export function finishPromptReservation(
+  sessionID: string,
+  reservation: PromptAsyncReservation,
+  dispatchAttempted: boolean,
+  postDispatchHoldMs: number,
+): void {
+  const current = promptAsyncReservations.get(sessionID)
+  if (current?.token !== reservation.token) {
+    return
+  }
+
+  if (dispatchAttempted && postDispatchHoldMs > 0) {
+    promptAsyncReservations.set(sessionID, {
+      ...reservation,
+      expiresAt: Date.now() + postDispatchHoldMs,
+    })
+    return
+  }
+  promptAsyncReservations.delete(sessionID)
+}
+
+export function deletePromptReservation(sessionID: string): void {
+  promptAsyncReservations.delete(sessionID)
+}
+
+export function clearPromptReservationsForTesting(): void {
+  promptAsyncReservations.clear()
+}
+
+export function reservationSourceMatches(
+  reservationSource: string,
+  expectedSource: string | readonly string[],
+  expectedPrefix?: PromptAsyncReservationReleaseOptions["reservedByPrefix"],
+): boolean {
+  if (typeof expectedSource === "string") {
+    if (reservationSource === expectedSource) {
+      return true
+    }
+  } else if (expectedSource.includes(reservationSource)) {
+    return true
+  }
+
+  if (expectedPrefix === undefined) {
+    return false
+  }
+
+  const prefixes = typeof expectedPrefix === "string" ? [expectedPrefix] : expectedPrefix
+  return prefixes
+    .filter((prefix) => prefix.length > 0 && prefix.endsWith(":"))
+    .some((prefix) => reservationSource.startsWith(prefix))
+}