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/examples/cli-demo/tests/cli-demo.spec.ts

@@ -45,7 +45,7 @@ async function composePrefix(ctx: Context): Promise<Message[]> {
   const agent = ctx.agentLoop.create(SessionId(`cli-demo-prefix-${randomUUID()}`), {}, { cwd: '/tmp' })
   const signal = new AbortController().signal
   const decision = await agentEvents(ctx, agent).waterfall(
-    'agent/pre-step', [], { turn: 1, step: 1, signal },
+    'agent/pre-step', { messages: [], turn: 1, step: 1, signal },
     () => Promise.resolve({ kind: 'enter', messages: [] }),
   )
   if (decision.kind === 'enter') {