fix(plugin): verify event hook compatibility with v1.4.0

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/features/background-agent/compaction-aware-message-resolver.ts

@@ -2,8 +2,16 @@ import { readdirSync, readFileSync } from "node:fs"
 import { join } from "node:path"
 import type { StoredMessage } from "../hook-message-injector"
 import { getCompactionAgentConfigCheckpoint } from "../../shared/compaction-agent-config-checkpoint"
+import {
+  hasCompactionPartInStorage,
+  isCompactionAgent,
+  isCompactionMessage,
+} from "../../shared/compaction-marker"
+
+export { isCompactionAgent } from "../../shared/compaction-marker"
 
 type SessionMessage = {
+  id?: string
   info?: {
     agent?: string
     model?: {
@@ -15,10 +23,7 @@ type SessionMessage = {
     modelID?: string
     tools?: StoredMessage["tools"]
   }
-}
-
-export function isCompactionAgent(agent: string | undefined): boolean {
-  return agent?.trim().toLowerCase() === "compaction"
+  parts?: Array<{ type?: string }>
 }
 
 function hasFullAgentAndModel(message: StoredMessage): boolean {
@@ -35,6 +40,10 @@ function hasPartialAgentOrModel(message: StoredMessage): boolean {
 }
 
 function convertSessionMessageToStoredMessage(message: SessionMessage): StoredMessage | null {
+  if (isCompactionMessage(message)) {
+    return null
+  }
+
   const info = message.info
   if (!info) {
     return null
@@ -138,7 +147,11 @@ export function findNearestMessageExcludingCompaction(
     for (const file of files) {
       try {
         const content = readFileSync(join(messageDir, file), "utf-8")
-        messages.push(JSON.parse(content) as StoredMessage)
+        const parsed = JSON.parse(content) as StoredMessage & { id?: string }
+        if (hasCompactionPartInStorage(parsed.id) || isCompactionAgent(parsed.agent)) {
+          continue
+        }
+        messages.push(parsed)
       } catch {
         continue
       }