fix(delegate-task): start child prompts reliably

Preserve delegated child prompt/bootstrap metadata for early runtime fallback before OpenCode has persisted the first user turn. Bind prompt gate calls to the SDK session receiver and keep completed background task lookup visible across plugin manager instances.

src/shared/delegated-child-session-bootstrap.ts

@@ -0,0 +1,71 @@
+import type { ModelFallbackControllerAccessor } from "../hooks/model-fallback"
+import { createInternalAgentTextPart } from "./internal-initiator-marker"
+import type { FallbackEntry } from "./model-requirements"
+import { SessionCategoryRegistry } from "./session-category-registry"
+
+export type DelegatedChildSessionRetryPart = {
+  type: "text"
+  text: string
+}
+
+export type DelegatedChildSessionBootstrap = {
+  retryParts: DelegatedChildSessionRetryPart[]
+  fallbackChain?: FallbackEntry[]
+  category?: string
+}
+
+const delegatedChildSessionBootstraps = new Map<string, DelegatedChildSessionBootstrap>()
+
+function cloneRetryParts(parts: DelegatedChildSessionRetryPart[]): DelegatedChildSessionRetryPart[] {
+  return parts.map((part) => ({ type: part.type, text: part.text }))
+}
+
+function cloneFallbackChain(fallbackChain: FallbackEntry[] | undefined): FallbackEntry[] | undefined {
+  return fallbackChain?.map((entry) => ({
+    ...entry,
+    providers: [...entry.providers],
+  }))
+}
+
+export function registerDelegatedChildSessionBootstrap(_args: {
+  sessionID: string
+  promptText: string
+  fallbackChain?: FallbackEntry[]
+  category?: string
+  modelFallbackControllerAccessor?: ModelFallbackControllerAccessor
+}): void {
+  const retryParts = [createInternalAgentTextPart(_args.promptText)]
+  const fallbackChain = cloneFallbackChain(_args.fallbackChain)
+  delegatedChildSessionBootstraps.set(_args.sessionID, {
+    retryParts,
+    ...(fallbackChain ? { fallbackChain } : {}),
+    ...(_args.category ? { category: _args.category } : {}),
+  })
+
+  _args.modelFallbackControllerAccessor?.setSessionFallbackChain(_args.sessionID, fallbackChain)
+  if (_args.category) {
+    SessionCategoryRegistry.register(_args.sessionID, _args.category)
+  }
+}
+
+export function getDelegatedChildSessionBootstrap(_sessionID: string): DelegatedChildSessionBootstrap | undefined {
+  const bootstrap = delegatedChildSessionBootstraps.get(_sessionID)
+  if (!bootstrap) {
+    return undefined
+  }
+
+  const fallbackChain = cloneFallbackChain(bootstrap.fallbackChain)
+  return {
+    retryParts: cloneRetryParts(bootstrap.retryParts),
+    ...(fallbackChain ? { fallbackChain } : {}),
+    ...(bootstrap.category ? { category: bootstrap.category } : {}),
+  }
+}
+
+export function clearDelegatedChildSessionBootstrap(_sessionID: string): void {
+  delegatedChildSessionBootstraps.delete(_sessionID)
+}
+
+export function clearAllDelegatedChildSessionBootstrap(): void {
+  delegatedChildSessionBootstraps.clear()
+}