feat(subagent): let ancestors interrupt descendants

interrupt_agent(agent_id) passes the calling agent as the ancestor
authority for ctx.subagents.interrupt(); the service verifies live
registry identity and recorded lineage, so a direct child or deeper
descendant stops with the same generic parameter while send_message keeps
its exact-direct-parent authority.

Discovery: list_agents gains an optional scope. descendants walks the new
SubagentService.listDescendants() — one lineage trace flattened in stable
pre-order across ordinary and one-shot intermediates, each entry carrying
its verified parentId and depth — and every status now comes from the
live Agent registry (running/idle/complete).

Refs #1535

scripts/gen-cordis-catalog.ts

@@ -172,6 +172,7 @@ export const LINK_MAP: Readonly<Record<string, string>> = {
   ContinuableStart: 'subagent.md',
   ContinuableStartSpec: 'subagent.md',
   CoordinatorMessageSource: 'subagent.md',
+  SubagentDescendantListEntry: 'subagent.md',
   SubagentFollowupOptions: 'subagent.md',
   SubagentInterruptAuthority: 'subagent.md',
   SubagentListEntry: 'subagent.md',

scripts/gen-tool-catalog.ts

@@ -399,10 +399,11 @@ const TOOL_PACKAGES: ToolPackage[] = [
     pkg: '@deepseek-ai/dsh-tool-subagent-control',
     dir: 'tool-subagent-control',
     source: {
+      interrupt_agent: 'packages/subagent/tool-subagent-control/src/index.ts',
       list_agents: 'packages/subagent/tool-subagent-control/src/list-agents.ts',
       send_message: 'packages/subagent/tool-subagent-control/src/index.ts',
     },
-    requires: ['ctx.tools', 'ctx.subagents', 'ctx.sessionProjections (list_agents catalog rows)'],
+    requires: ['ctx.tools', 'ctx.subagents', 'ctx.agents and ctx.sessionProjections (list_agents only)'],
     writes: ['tool/call', 'tool/result', 'child session events through ctx.subagents'],
     async mount(ctx) {
       await ctx.plugin(SubagentService)
@@ -414,7 +415,7 @@ const TOOL_PACKAGES: ToolPackage[] = [
       await ctx.plugin(ToolSubagentListAgents)
     },
     note:
-      'The globally named control tools over continuable background subagents: provider-bound `tool-subagent` instances register distinct delegation tools, while this package registers `send_message` once, plus `list_agents` from its separately loaded `/list-agents` plugin (whose catalog rows are served through the sessionProjections registry).',
+      'The globally named control tools over continuable background subagents: provider-bound `tool-subagent` instances register distinct delegation tools, while this package registers `send_message` and `interrupt_agent` once, plus `list_agents` from its separately loaded `/list-agents` plugin (whose catalog rows use the sessionProjections and live Agent registries).',
   },
   {
     pkg: '@deepseek-ai/dsh-tool-subagent-report',

scripts/type-equiv.manifest.json

@@ -1155,6 +1155,11 @@
       "symbol": "SubagentInterruptAuthority",
       "source": "packages/subagent/subagent/src/continuation.ts"
     },
+    {
+      "doc": "docs/core-data-structures/subagent.md",
+      "symbol": "SubagentDescendantListEntry",
+      "source": "packages/subagent/subagent/src/list-children.ts"
+    },
     {
       "doc": "docs/core-data-structures/subagent.md",
       "symbol": "ContinuableStart",