Add tmux pane management for background agent sessions (#1094)

* feat(config): add TmuxConfigSchema for tmux subagent pane management

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

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

* feat(shared): add tmux module structure

* feat(shared/tmux): implement tmux pane utilities

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

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

* test(tmux-subagent): add TmuxSessionManager tests (TDD RED)

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

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

* feat(tmux-subagent): implement TmuxSessionManager

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

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

* feat(integration): wire TmuxSessionManager with 500ms delay

- Task 5: Add 500ms delay in BackgroundManager after session creation
- Task 6: Wire TmuxSessionManager event handlers (session.created/deleted)
- Both changes integrate tmux pane management into plugin lifecycle

Co-authored-by: Sisyphus <ultrawork@oh-my-opencode>

---------

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

src/features/background-agent/manager.ts

@@ -7,7 +7,8 @@ import type {
 } from "./types"
 import { log, getAgentToolRestrictions } from "../../shared"
 import { ConcurrencyManager } from "./concurrency"
-import type { BackgroundTaskConfig } from "../../config/schema"
+import type { BackgroundTaskConfig, TmuxConfig } from "../../config/schema"
+import { isInsideTmux } from "../../shared/tmux"
 
 import { subagentSessions } from "../claude-code-session-state"
 import { getTaskToastManager } from "../task-toast-manager"
@@ -68,12 +69,16 @@ export class BackgroundManager {
   private concurrencyManager: ConcurrencyManager
   private shutdownTriggered = false
   private config?: BackgroundTaskConfig
-
+  private tmuxEnabled: boolean
 
   private queuesByKey: Map<string, QueueItem[]> = new Map()
   private processingKeys: Set<string> = new Set()
 
-  constructor(ctx: PluginInput, config?: BackgroundTaskConfig) {
+  constructor(
+    ctx: PluginInput,
+    config?: BackgroundTaskConfig,
+    tmuxConfig?: TmuxConfig
+  ) {
     this.tasks = new Map()
     this.notifications = new Map()
     this.pendingByParent = new Map()
@@ -81,6 +86,7 @@ export class BackgroundManager {
     this.directory = ctx.directory
     this.concurrencyManager = new ConcurrencyManager(config)
     this.config = config
+    this.tmuxEnabled = tmuxConfig?.enabled ?? false
     this.registerProcessCleanup()
   }
 
@@ -222,6 +228,11 @@ export class BackgroundManager {
     const sessionID = createResult.data.id
     subagentSessions.add(sessionID)
 
+    // Wait for TmuxSessionManager to spawn pane via event hook
+    if (this.tmuxEnabled && isInsideTmux()) {
+      await new Promise(r => setTimeout(r, 500))
+    }
+
     // Update task to running state
     task.status = "running"
     task.startedAt = new Date()