docs(subagent): record the public interrupt in the continuation contract docs

The continuable-subagent core-data page and the continuation lifecycle
Agent Note claimed no public subagent cancellation existed; interrupt()
is now that one public stop. Both pages and their Chinese counterparts
state the shipped contract and link the owning interrupt note.

Refs #1535

scripts/type-equiv.manifest.json

@@ -1150,6 +1150,11 @@
       "symbol": "SubagentFollowupOptions",
       "source": "packages/subagent/subagent/src/continuation.ts"
     },
+    {
+      "doc": "docs/core-data-structures/subagent.md",
+      "symbol": "SubagentInterruptAuthority",
+      "source": "packages/subagent/subagent/src/continuation.ts"
+    },
     {
       "doc": "docs/core-data-structures/subagent.md",
       "symbol": "ContinuableStart",