feat(subagent): add current-turn interrupt RPC

ctx.subagents.interrupt() stops one live continuable child's current turn
via Agent.cancel(cause, { keepInbox: true }) under either a human durable
parent address or an exact live ancestor Agent. Fire-and-return: admission
is synchronous, quiescence is not awaited. Pending inbox work, the
Activation, and published descendants are preserved; only a later waking
send resumes the parked FIFO queue. Absent, one-shot, and disposing
targets are accepted no-ops.

The new Host RPC subagent.interrupt calls only that primitive with user
authority — no catalog, history, persistence, or parent-registry lookup —
so a live child stays stoppable while its parent Agent is offline.

Refs #1535

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

@@ -928,6 +928,10 @@ export const SERVICE_API: readonly ServiceApiEntry[] = [
         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: 'interrupt(targetSessionId: SessionId, authority: SubagentInterruptAuthority): void',
+        jsDoc: '/**\n * Interrupt one live continuable child\'s current turn under a human parent\n * address or an exact live ancestor Agent. Fire-and-return: the cancel\n * signal is issued before this returns, but the target may keep running\n * until it observes the signal. Pending inbox work, the Activation, and\n * published descendants are preserved; only a later waking send resumes the\n * parked FIFO queue. An absent target — including a one-shot or unknown id —\n * is an accepted no-op, as is a manager-less composition, which cannot own a\n * live Activation.\n * @param targetSessionId - the durable child session id to interrupt.\n * @param authority - the human parent address or exact live ancestor Agent.\n * @throws {SubagentError} `UNAUTHORIZED` when the authority does not own the\n *   live target.\n */',
+      },
       {
         signature: 'async reportFrom( child: Agent, content: ContentBlock[], options: SubagentReportOptions, ): Promise<MessageId>',
         jsDoc: '/**\n * Deliver selected content from one live continuable child to its durable\n * direct parent. The child is the authority credential; callers cannot name a\n * recipient. Reporting does not conclude the child\'s turn or Activation.\n * @param child - exact live reporting child.\n * @param content - selected model-facing content.\n * @param options - parent scheduling and pre-acceptance cancellation.\n * @returns the stable identity of the parent-accepted message.\n * @throws when continuation services are unavailable, sender authorization\n *   fails, or the direct parent is not live.\n */',
@@ -2787,6 +2791,10 @@ export const TYPE_API: readonly TypeApiEntry[] = [
     name: 'SubagentFollowupOptions',
     declaration: 'export interface SubagentFollowupOptions {\n    readonly source: MessageSource;\n    readonly signal: AbortSignal;\n}',
   },
+  {
+    name: 'SubagentInterruptAuthority',
+    declaration: 'export type SubagentInterruptAuthority = {\n    readonly kind: \'user\';\n    readonly parentSessionId: SessionId;\n} | {\n    readonly kind: \'ancestor\';\n    readonly agent: Agent;\n};',
+  },
   {
     name: 'SubagentListEntry',
     declaration: 'export type SubagentListEntry = {\n    readonly kind: \'child\';\n    readonly id: SessionId;\n    readonly activity: \'running\' | \'inactive\';\n    readonly hasChildren: boolean;\n} & ({\n    readonly mode: \'one-shot\';\n    readonly label?: string;\n} | {\n    readonly mode: \'continuable\';\n    readonly label: string;\n}) | {\n    readonly kind: \'diagnostic\';\n    readonly id: SessionId;\n    readonly reason: \'corrupt\' | \'unsupported\' | \'unavailable\';\n};',