refactor(subagent): drop host-user authority and split lifecycle publication

Remove the host-user continuation capability and the public residency query,
then separate the seam's public event payloads from its internal lifecycle
control interfaces.

`followup()` now takes the exact live direct parent `Agent` instead of a
`SubagentAuthority` union. No production adapter ever supplied user authority,
so the `UserAuthorityGrant` brand token existed only to stop a forged
discriminant from bypassing the direct-parent check — deleting the branch
retires the token, its mint method, and that attack surface together.

Narrowing `parent` from `Agent | undefined` to `Agent` removes three special
cases, including the path where a parentless epoch dispatched its lifecycle
events unscoped. Scoped-versus-global dispatch is now decided by the event, not
by whether a caller happened to have a parent.

`activationState()` had no caller; `ActivationState`, `ActivationObserver`, and
`ContinuationHost` are package-private.

New `src/lifecycle.ts` owns the contained emitter, the one-shot run observer,
and the Activation observer, while `SubagentRunInfo`/`SubagentRunEndInfo` move
to `src/types.ts` beside the other consumer-facing contracts. Those payloads are
public API — dsh-jsonrpc, hooks-claude, and the package invariant all consume
them — whereas the observer is a contract between two in-package collaborators,
so they no longer share a home merely for both being lifecycle-shaped. The
service keeps ownership of the scope carrier: `scopeTarget()` composes the
service's own context filter, so a narrowed stand-in would silently change
scope filtering.

Also drops now-unused dsh-tasks-local and dsh-tool-tasks dev dependencies, and
corrects the README claim that a pre-residency failure emits a terminal edge —
that path only ever rethrew.

packages/cordis/tool-cordis/src/api-catalog.ts

@@ -889,16 +889,8 @@ export const SERVICE_API: readonly ServiceApiEntry[] = [
         jsDoc: '/**\n * Establish one durable continuable child and deliver its initial prompt.\n * Resolves when the child\'s inbox accepts that prompt, without waiting for the\n * turn to start or for the message to reach the Session log; any earlier\n * failure rejects with no ids and rolls back the child entirely.\n * @param spec - provider, delegation request, and caller cancellation.\n * @returns the durable child id and the accepted prompt\'s message id.\n * @throws when continuation services are unavailable or materialization fails.\n */',
       },
       {
-        signature: 'async followup( authority: SubagentAuthority, childId: SessionId, content: ContentBlock[], options: SubagentFollowupOptions, ): Promise<MessageId>',
-        jsDoc: '/**\n * Deliver one later message to a continuable child as its next FIFO turn. A\n * resident child\'s Agent inbox accepts it directly (waking a `waiting`\n * Activation), while an absent one is cold-resumed from its persisted\n * Session. The Agent inbox is the only queue, so parent and user messages\n * share one observable order.\n * @param authority - trusted parent or user authority for this delivery.\n * @param childId - durable child session id.\n * @param content - user-role content to deliver.\n * @param options - durable provenance and caller cancellation, which stops the\n *   operation only before inbox acceptance.\n * @returns the accepted message\'s inbox id.\n * @throws when continuation services are unavailable, authority is rejected,\n *   or the message was not admitted.\n */',
-      },
-      {
-        signature: 'userAuthority(): SubagentAuthority',
-        jsDoc: '/**\n * Host-user authority for continuable operations, which may continue any\n * durable child without its parent. A composition passes this only to a\n * trusted host adapter carrying real human interaction; a model-facing tool\n * uses `{ kind: \'parent\', agent }` from its own execution context instead.\n * @returns the authority a host adapter supplies to {@link followup}.\n */',
-      },
-      {
-        signature: 'activationState(childId: SessionId): ActivationState | undefined',
-        jsDoc: '/**\n * Read one durable child\'s live residency state.\n * @param childId - durable child session id.\n * @returns its Activation state, or `undefined` when no Activation is live.\n * @throws when continuation services are unavailable.\n */',
+        signature: 'async followup( parent: Agent, childId: SessionId, content: ContentBlock[], options: SubagentFollowupOptions, ): Promise<MessageId>',
+        jsDoc: '/**\n * Deliver one later message to a continuable child as its next FIFO turn. A\n * resident child\'s Agent inbox accepts it directly (waking a `waiting`\n * Activation), while an absent one is cold-resumed from its persisted\n * Session. The Agent inbox is the only queue, so every accepted message has\n * one observable order.\n * @param parent - the exact live direct parent authorizing this delivery.\n * @param childId - durable child session id.\n * @param content - user-role content to deliver.\n * @param options - durable provenance and caller cancellation, which stops the\n *   operation only before inbox acceptance.\n * @returns the accepted message\'s inbox id.\n * @throws when continuation services are unavailable, parent authority is\n *   rejected, or the message was not admitted.\n */',
       },
       {
         signature: 'async drainContinuable(): Promise<void>',
@@ -1579,10 +1571,6 @@ export const EVENT_API: readonly EventApiEntry[] = [
 
 /** Shapes of every exported type the SERVICE_API signatures reference (transitively), sorted by name. */
 export const TYPE_API: readonly TypeApiEntry[] = [
-  {
-    name: 'ActivationState',
-    declaration: 'export type ActivationState = \'running\' | \'waiting\' | \'settled\';',
-  },
   {
     name: 'AdapterRegistrationHandle',
     declaration: 'export interface AdapterRegistrationHandle {\n    (): void;\n    replace(providers: string[]): void;\n}',
@@ -2695,10 +2683,6 @@ export const TYPE_API: readonly TypeApiEntry[] = [
     name: 'StreamChunk',
     declaration: 'export type StreamChunk = {\n    type: \'block-start\';\n    index: number;\n    blockType: ContentBlockType;\n} | {\n    type: \'text-delta\';\n    index: number;\n    text: string;\n} | {\n    type: \'reasoning-delta\';\n    index: number;\n    text: string;\n} | {\n    type: \'tool-call-delta\';\n    index: number;\n    id: CallId;\n    name?: string;\n    argumentsDelta: string;\n} | {\n    type: \'block-end\';\n    index: number;\n    block: ContentBlock;\n} | {\n    type: \'usage\';\n    usage: TokenUsage;\n} | {\n    type: \'finish\';\n    reason: FinishReason;\n    replayState?: unknown;\n};',
   },
-  {
-    name: 'SubagentAuthority',
-    declaration: 'export type SubagentAuthority = {\n    readonly kind: \'parent\';\n    readonly agent: Agent;\n} | {\n    readonly kind: \'user\';\n    readonly grant: UserAuthorityGrant;\n};',
-  },
   {
     name: 'SubagentCapabilities',
     declaration: 'export interface SubagentCapabilities {\n    readonly outputSchema: boolean;\n    readonly depthLimit: boolean;\n    readonly toolFilter: boolean;\n    readonly persona: boolean;\n}',
@@ -3039,10 +3023,6 @@ export const TYPE_API: readonly TypeApiEntry[] = [
     name: 'TypertTypeModel',
     declaration: 'export interface TypertTypeModel {\n    readonly name: string;\n    readonly declaration: string;\n}',
   },
-  {
-    name: 'UserAuthorityGrant',
-    declaration: 'export type UserAuthorityGrant = {\n    readonly __brand: \'SubagentUserAuthority\';\n};',
-  },
   {
     name: 'UserInteractionProvider',
     declaration: 'export interface UserInteractionProvider {\n    ask(request: AskUserQuestionRequest): Promise<AskUserQuestionAnswer>;\n}',