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/cli-mock-llm.ts

@@ -59,7 +59,7 @@ export const inject = ['llm']
 /** Register the keyless `cli-mock` adapter. */
 export function apply(ctx: Context): void {
   ctx.llm.registerAdapter(['cli-mock'], new CliMockAdapter())
-  ctx.on('agent/request', async (_agent, _turn, step, _signal, next) => {
+  ctx.on('agent/request', async ({ step }, next) => {
     const config = await next()
     return step === 2 ? { ...config, reasoningEffort: OFF } : config
   })

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',