feat(hooks): add /stop-continuation command to halt all continuation mechanisms (#1316)

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)

Co-authored-by: justsisyphus <justsisyphus@users.noreply.github.com>
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/hooks/stop-continuation-guard/index.ts

@@ -0,0 +1,54 @@
+import type { PluginInput } from "@opencode-ai/plugin"
+import { log } from "../../shared/logger"
+
+const HOOK_NAME = "stop-continuation-guard"
+
+export interface StopContinuationGuard {
+  event: (input: { event: { type: string; properties?: unknown } }) => Promise<void>
+  stop: (sessionID: string) => void
+  isStopped: (sessionID: string) => boolean
+  clear: (sessionID: string) => void
+}
+
+export function createStopContinuationGuardHook(
+  _ctx: PluginInput
+): StopContinuationGuard {
+  const stoppedSessions = new Set<string>()
+
+  const stop = (sessionID: string): void => {
+    stoppedSessions.add(sessionID)
+    log(`[${HOOK_NAME}] Continuation stopped for session`, { sessionID })
+  }
+
+  const isStopped = (sessionID: string): boolean => {
+    return stoppedSessions.has(sessionID)
+  }
+
+  const clear = (sessionID: string): void => {
+    stoppedSessions.delete(sessionID)
+    log(`[${HOOK_NAME}] Continuation guard cleared for session`, { sessionID })
+  }
+
+  const event = async ({
+    event,
+  }: {
+    event: { type: string; properties?: unknown }
+  }): Promise<void> => {
+    const props = event.properties as Record<string, unknown> | undefined
+
+    if (event.type === "session.deleted") {
+      const sessionInfo = props?.info as { id?: string } | undefined
+      if (sessionInfo?.id) {
+        clear(sessionInfo.id)
+        log(`[${HOOK_NAME}] Session deleted: cleaned up`, { sessionID: sessionInfo.id })
+      }
+    }
+  }
+
+  return {
+    event,
+    stop,
+    isStopped,
+    clear,
+  }
+}