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).

examples/headless-agent/tests/fixtures/goal-domain/seed-goal.ts

@@ -7,7 +7,7 @@ export const name = 'seed-goal'
 export const inject = ['goals']
 
 export function apply(ctx: Context): void {
-  ctx.on('agent/pre-step', (agent, _messages, _context, next) => {
+  ctx.on('agent/pre-step', ({ agent }, next) => {
     if (ctx.goals.get(agent) === undefined) {
       ctx.goals.create(agent, {
         objective: 'Prove the composed goal survives in the session log',