fix: add missing bashOutput method and bashSnapshots property to ACP Agent

Required by upstream v1.2.20 bash output streaming feature.

Co-Authored-By: Kai (Claude Opus 4.6) <noreply@anthropic.com>

Author: kulvirgit

packages/opencode/src/acp/agent.ts

@@ -42,7 +42,7 @@ import { Config } from "@/config/config"
 import { Todo } from "@/session/todo"
 import { z } from "zod"
 import { LoadAPIKeyError } from "ai"
-import type { AssistantMessage, Event, OpencodeClient, SessionMessageResponse } from "@opencode-ai/sdk/v2"
+import type { AssistantMessage, Event, OpencodeClient, SessionMessageResponse, ToolPart } from "@opencode-ai/sdk/v2"
 import { applyPatch } from "diff"
 
 type ModeOption = { id: string; name: string; description?: string }
@@ -136,6 +136,7 @@ export namespace ACP {
     private sessionManager: ACPSessionManager
     private eventAbort = new AbortController()
     private eventStarted = false
+    private bashSnapshots = new Map<string, string>()
     private permissionQueues = new Map<string, Promise<void>>()
     private permissionOptions: PermissionOption[] = [
       { optionId: "once", kind: "allow_once", name: "Allow once" },
@@ -1467,6 +1468,14 @@ export namespace ACP {
         { throwOnError: true },
       )
     }
+
+    private bashOutput(part: ToolPart) {
+      if (part.tool !== "bash") return
+      if (!("metadata" in part.state) || !part.state.metadata || typeof part.state.metadata !== "object") return
+      const output = part.state.metadata["output"]
+      if (typeof output !== "string") return
+      return output
+    }
   }
 
   function toToolKind(toolName: string): ToolKind {