fix: remove task-continuation-enforcer references after dev merge

Dev removed task-continuation-enforcer entirely. Remove all remaining
references from plugin hooks, event handler, tool-execute-before, and
config schema to align with origin/dev.

src/plugin/event.ts

@@ -33,7 +33,6 @@ export function createEventHandler(args: {
     await Promise.resolve(hooks.backgroundNotificationHook?.event?.(input))
     await Promise.resolve(hooks.sessionNotification?.(input))
     await Promise.resolve(hooks.todoContinuationEnforcer?.handler?.(input))
-    await Promise.resolve(hooks.taskContinuationEnforcer?.handler?.(input))
     await Promise.resolve(hooks.unstableAgentBabysitter?.event?.(input))
     await Promise.resolve(hooks.contextWindowMonitor?.event?.(input))
     await Promise.resolve(hooks.directoryAgentsInjector?.event?.(input))