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/host/apiproxy/src/api-proxy.ts

@@ -2595,10 +2595,10 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
           ctx.on('session/disposed', (session: Session) => {
             queue.push(frame({ type: 'host/session-removed', sessionId: session.id }))
           }),
-          ctx.on('agent/status', (agent: Agent, status: AgentStatus) => {
+          ctx.on('agent/status', ({ agent, status }: { agent: Agent; status: AgentStatus }) => {
             queue.push(frame({ type: 'host/session-status', sessionId: agent.id, running: status === 'running' }))
           }),
-          ctx.on('agent/error', (agent: Agent, _turn: number, _step: number, error: unknown) => {
+          ctx.on('agent/error', ({ agent, error }: { agent: Agent; error: unknown }) => {
             queue.push(frame({ type: 'host/agent-error', sessionId: agent.id, message: errorChain(error) }))
           }),
           ctx.on('domain/changed', (change) => {