fix(acp): forward inbound media attachments through ACP topic binding turns

When a Telegram topic is bound to an agent via ACP, images and files sent
in the topic were silently dropped — the agent received only a placeholder
tag instead of the actual image content. The media was correctly downloaded
to ~/.openclaw/media/inbound/ but never forwarded through the ACP turn.

Changes:
- Add AcpTurnAttachment type to AcpRunTurnInput and AcpRuntimeTurnInput
- In dispatch-acp: read MediaPaths/MediaTypes from FinalizedMsgContext,
  read each file and base64-encode it as an attachment for the ACP turn
- In manager.core: thread attachments through to runtime.runTurn()
- In acpx runtime: when attachments are present, serialize stdin as a
  JSON content-blocks array (text + image blocks) instead of plain text,
  matching the ACP protocol's standard multi-modal message format

Fixes #40978

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

extensions/acpx/src/runtime.ts

@@ -310,7 +310,15 @@ export class AcpxRuntime implements AcpRuntime {
       // Ignore EPIPE when the child exits before stdin flush completes.
     });
 
-    child.stdin.end(input.text);
+    if (input.attachments && input.attachments.length > 0) {
+      const blocks: unknown[] = [{ type: "text", text: input.text }];
+      for (const attachment of input.attachments) {
+        blocks.push({ type: "image", mimeType: attachment.mediaType, data: attachment.data });
+      }
+      child.stdin.end(JSON.stringify(blocks));
+    } else {
+      child.stdin.end(input.text);
+    }
 
     let stderr = "";
     child.stderr.on("data", (chunk) => {

src/acp/control-plane/manager.core.ts

@@ -655,6 +655,7 @@ export class AcpSessionManager {
         for await (const event of runtime.runTurn({
           handle,
           text: input.text,
+          attachments: input.attachments,
           mode: input.mode,
           requestId: input.requestId,
           signal: combinedSignal,

src/acp/control-plane/manager.types.ts

@@ -47,10 +47,16 @@ export type AcpInitializeSessionInput = {
   backendId?: string;
 };
 
+export type AcpTurnAttachment = {
+  mediaType: string;
+  data: string;
+};
+
 export type AcpRunTurnInput = {
   cfg: OpenClawConfig;
   sessionKey: string;
   text: string;
+  attachments?: AcpTurnAttachment[];
   mode: AcpRuntimePromptMode;
   requestId: string;
   signal?: AbortSignal;

src/acp/runtime/types.ts

@@ -39,9 +39,15 @@ export type AcpRuntimeEnsureInput = {
   env?: Record<string, string>;
 };
 
+export type AcpRuntimeTurnAttachment = {
+  mediaType: string;
+  data: string;
+};
+
 export type AcpRuntimeTurnInput = {
   handle: AcpRuntimeHandle;
   text: string;
+  attachments?: AcpRuntimeTurnAttachment[];
   mode: AcpRuntimePromptMode;
   requestId: string;
   signal?: AbortSignal;

src/auto-reply/reply/dispatch-acp.ts

@@ -1,4 +1,6 @@
+import fs from "node:fs/promises";
 import { getAcpSessionManager } from "../../acp/control-plane/manager.js";
+import type { AcpTurnAttachment } from "../../acp/control-plane/manager.types.js";
 import { resolveAcpAgentPolicyError, resolveAcpDispatchPolicyError } from "../../acp/policy.js";
 import { formatAcpRuntimeErrorText } from "../../acp/runtime/error-text.js";
 import { toAcpRuntimeError } from "../../acp/runtime/errors.js";
@@ -57,6 +59,29 @@ function resolveAcpPromptText(ctx: FinalizedMsgContext): string {
   ]).trim();
 }
 
+async function resolveAcpAttachments(ctx: FinalizedMsgContext): Promise<AcpTurnAttachment[]> {
+  const paths = ctx.MediaPaths;
+  const types = ctx.MediaTypes;
+  if (!Array.isArray(paths) || paths.length === 0) {
+    return [];
+  }
+  const results: AcpTurnAttachment[] = [];
+  for (let i = 0; i < paths.length; i++) {
+    const filePath = paths[i];
+    const mediaType = Array.isArray(types) ? (types[i] ?? "application/octet-stream") : "application/octet-stream";
+    if (typeof filePath !== "string" || !filePath.trim()) {
+      continue;
+    }
+    try {
+      const buf = await fs.readFile(filePath);
+      results.push({ mediaType, data: buf.toString("base64") });
+    } catch {
+      // Skip unreadable files — do not block the text turn.
+    }
+  }
+  return results;
+}
+
 function resolveCommandCandidateText(ctx: FinalizedMsgContext): string {
   return resolveFirstContextText(ctx, ["CommandBody", "BodyForCommands", "RawBody", "Body"]).trim();
 }
@@ -189,7 +214,8 @@ export async function tryDispatchAcpReply(params: {
   });
 
   const promptText = resolveAcpPromptText(params.ctx);
-  if (!promptText) {
+  const attachments = await resolveAcpAttachments(params.ctx);
+  if (!promptText && attachments.length === 0) {
     const counts = params.dispatcher.getQueuedCounts();
     delivery.applyRoutedCounts(counts);
     params.recordProcessed("completed", { reason: "acp_empty_prompt" });
@@ -251,6 +277,7 @@ export async function tryDispatchAcpReply(params: {
       cfg: params.cfg,
       sessionKey,
       text: promptText,
+      attachments: attachments.length > 0 ? attachments : undefined,
       mode: "prompt",
       requestId: resolveAcpRequestId(params.ctx),
       onEvent: async (event) => await projector.onEvent(event),