refactor(agent): unify agent-scoped event signatures as payload objects

All agent/* and agent-loop/config-start-failed events take one payload
object carrying the agent subject; waterfall/serial payloads require a
signal and keep next as the final argument. PreStepContext and
RequestFailureContext are unfolded into payloads and retired.
goal/changed follows the same shape so agentEvents keeps its listener
error containment. ReactLoopAgent builds its scope carrier once in the
constructor. Regenerates scope resolvers, tool-cordis api catalog, and
docs catalogs; updates all affected listeners, tests, and the
core-data-structures docs (en + zh).

packages/plan/plan-mode/src/index.ts

@@ -202,9 +202,7 @@ export class PlanModeService extends Service {
     // the session. A failed append remains pending for a later boundary, and
     // policy cannot block the step.
     ctx.on('agent/pre-step', async (
-      agent,
-      _messages,
-      { signal },
+      { agent, signal },
       next,
     ): Promise<PreStepDecision> => {
       const decision = await next()