Prepare prompt file attachments for future UI (#1376)

* Support file uploads to agents

* Harden prompt file upload handling

* Fix duplicate upload retry handling

* Update relay reconnect tests for queued messages

* Make upload timeout track idle progress

* Clean failed upload directories

packages/client/src/daemon-client.ts

@@ -22,6 +22,7 @@ import type {
   CreateAgentRequestMessage,
   CreatePaseoWorktreeRequest,
   FileDownloadTokenResponse,
+  FileUploadResponse,
   FileExplorerResponse,
   FetchAgentTimelineResponseMessage,
   GitSetupOptions,
@@ -90,6 +91,7 @@ import { isRelayClientWebSocketUrl } from "@getpaseo/protocol/daemon-endpoints";
 import {
   asUint8Array,
   decodeFileTransferFrame,
+  encodeFileTransferFrame,
   decodeTerminalStreamFrame,
   FileTransferOpcode,
   TerminalStreamOpcode,
@@ -318,6 +320,15 @@ export interface FileReadResult {
   kind: LegacyFileExplorerFilePayload["kind"];
   modifiedAt: string;
 }
+export interface FileUploadInput {
+  fileName: string;
+  mimeType: string;
+  bytes: Uint8Array | ArrayBuffer;
+  modifiedAt?: string;
+  requestId?: string;
+  chunkSize?: number;
+}
+export type FileUploadResult = FileUploadResponse["payload"];
 type FileDownloadTokenPayload = FileDownloadTokenResponse["payload"];
 type ListProviderFeaturesPayload = ListProviderFeaturesResponseMessage["payload"];
 type ListProviderModelsPayload = ListProviderModelsResponseMessage["payload"];
@@ -3316,6 +3327,63 @@ export class DaemonClient {
     }
   }
 
+  async uploadFile(input: FileUploadInput): Promise<FileUploadResult> {
+    const bytes = asUint8Array(input.bytes);
+    if (!bytes) {
+      throw new Error("File bytes are required.");
+    }
+    const resolvedRequestId = this.createRequestId(input.requestId);
+    const modifiedAt = input.modifiedAt ?? new Date().toISOString();
+    const responsePromise = this.sendCorrelatedRequest({
+      requestId: resolvedRequestId,
+      message: {
+        type: "file.upload.request",
+        fileName: input.fileName,
+        mimeType: input.mimeType,
+        size: bytes.byteLength,
+        modifiedAt,
+        requestId: resolvedRequestId,
+      },
+      responseType: "file.upload.response",
+      timeout: 60000,
+      options: { skipQueue: true },
+    });
+
+    this.sendBinaryFrame(
+      encodeFileTransferFrame({
+        opcode: FileTransferOpcode.FileBegin,
+        requestId: resolvedRequestId,
+        metadata: {
+          mime: input.mimeType,
+          size: bytes.byteLength,
+          encoding: "binary",
+          modifiedAt,
+          fileName: input.fileName,
+        },
+      }),
+    );
+
+    const chunkSize = input.chunkSize ?? 1024 * 1024;
+    for (let offset = 0; offset < bytes.byteLength; offset += chunkSize) {
+      this.sendBinaryFrame(
+        encodeFileTransferFrame({
+          opcode: FileTransferOpcode.FileChunk,
+          requestId: resolvedRequestId,
+          payload: bytes.subarray(offset, Math.min(offset + chunkSize, bytes.byteLength)),
+        }),
+      );
+    }
+
+    this.sendBinaryFrame(
+      encodeFileTransferFrame({
+        opcode: FileTransferOpcode.FileEnd,
+        requestId: resolvedRequestId,
+      }),
+    );
+
+    return responsePromise;
+  }
+
   async requestDownloadToken(
     cwd: string,
     path: string,