feat(hooks): add trigger and channelId to plugin hook agent context (#28623)

* feat(hooks): add trigger and channelId to plugin hook agent context

Adds `trigger` and `channelId` fields to `PluginHookAgentContext` so
plugins can determine what initiated the agent run and which channel
it originated from, without session-key parsing or Redis bridging.

trigger values: "user", "heartbeat", "cron", "memory"
channelId values: "telegram", "discord", "whatsapp", etc.

Both fields are threaded through run.ts and attempt.ts hookCtx so all
hook phases receive them (before_model_resolve, before_prompt_build,
before_agent_start, llm_input, llm_output, agent_end).

channelId falls back from messageChannel to messageProvider when the
former is not set. followup-runner passes originatingChannel so queued
followup runs also carry channel context.

* docs(changelog): note hook context parity fix for #28623

---------

Co-authored-by: Vincent Koc <vincentkoc@ieee.org>

src/auto-reply/reply/agent-runner-execution.ts

@@ -295,6 +295,7 @@ export async function runAgentTurnWithFallback(params: {
           });
           return runEmbeddedPiAgent({
             ...embeddedContext,
+            trigger: params.isHeartbeat ? "heartbeat" : "user",
             groupId: resolveGroupSessionKey(params.sessionCtx)?.id,
             groupChannel:
               params.sessionCtx.GroupChannel?.trim() ?? params.sessionCtx.GroupSubject?.trim(),

src/auto-reply/reply/agent-runner-memory.ts

@@ -487,6 +487,7 @@ export async function runMemoryFlushIfNeeded(params: {
           ...embeddedContext,
           ...senderContext,
           ...runBaseParams,
+          trigger: "memory",
           prompt: resolveMemoryFlushPromptForRun({
             prompt: memoryFlushSettings.prompt,
             cfg: params.cfg,

src/auto-reply/reply/followup-runner.ts

@@ -157,6 +157,8 @@ export function createFollowupRunner(params: {
               sessionId: queued.run.sessionId,
               sessionKey: queued.run.sessionKey,
               agentId: queued.run.agentId,
+              trigger: "user",
+              messageChannel: queued.originatingChannel ?? undefined,
               messageProvider: queued.run.messageProvider,
               agentAccountId: queued.run.agentAccountId,
               messageTo: queued.originatingTo,