refactor(tmux-subagent): state-first architecture with decision engine (#1125)

* refactor(tmux-subagent): add state-first architecture with decision engine

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

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

* feat(tmux): add pane spawn callbacks for background and sync sessions

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

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

---------

Co-authored-by: justsisyphus <justsisyphus@users.noreply.github.com>
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/tools/delegate-task/tools.ts

@@ -151,6 +151,12 @@ export function resolveCategoryConfig(
   return { config, promptAppend, model }
 }
 
+export interface SyncSessionCreatedEvent {
+  sessionID: string
+  parentID: string
+  title: string
+}
+
 export interface DelegateTaskToolOptions {
   manager: BackgroundManager
   client: OpencodeClient
@@ -159,6 +165,7 @@ export interface DelegateTaskToolOptions {
   gitMasterConfig?: GitMasterConfig
   sisyphusJuniorModel?: string
   browserProvider?: BrowserAutomationProvider
+  onSyncSessionCreated?: (event: SyncSessionCreatedEvent) => Promise<void>
 }
 
 export interface BuildSystemContentInput {
@@ -181,7 +188,7 @@ export function buildSystemContent(input: BuildSystemContentInput): string | und
 }
 
 export function createDelegateTask(options: DelegateTaskToolOptions): ToolDefinition {
-  const { manager, client, directory, userCategories, gitMasterConfig, sisyphusJuniorModel, browserProvider } = options
+  const { manager, client, directory, userCategories, gitMasterConfig, sisyphusJuniorModel, browserProvider, onSyncSessionCreated } = options
 
   const allCategories = { ...DEFAULT_CATEGORIES, ...userCategories }
   const categoryNames = Object.keys(allCategories)
@@ -850,6 +857,18 @@ To continue this session: session_id="${task.sessionID}"`
         syncSessionID = sessionID
         subagentSessions.add(sessionID)
 
+        if (onSyncSessionCreated) {
+          log("[delegate_task] Invoking onSyncSessionCreated callback", { sessionID, parentID: ctx.sessionID })
+          await onSyncSessionCreated({
+            sessionID,
+            parentID: ctx.sessionID,
+            title: args.description,
+          }).catch((err) => {
+            log("[delegate_task] onSyncSessionCreated callback failed", { error: String(err) })
+          })
+          await new Promise(r => setTimeout(r, 200))
+        }
+
         taskId = `sync_${sessionID.slice(0, 8)}`
         const startTime = new Date()