Fix loop response: service stdout is raw text, not base64

The service log API sends stdout data as plain text strings, not
base64-encoded bytes. Data(base64Encoded:) was silently returning nil
for every chunk, causing all responses to be empty.

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

Author: zmanian

Wisp/Services/LoopManager.swift

@@ -348,8 +348,8 @@ final class LoopManager {
                     for try await event in stream {
                         try Task.checkCancellation()
                         gotData = true
-                        guard event.type == .stdout, let base64Data = event.data else { continue }
-                        guard let rawData = Data(base64Encoded: base64Data) else { continue }
+                        guard event.type == .stdout, let stdoutText = event.data else { continue }
+                        let rawData = Data(stdoutText.utf8)
                         let claudeEvents = await parser.parse(data: rawData)
                         for claudeEvent in claudeEvents {
                             switch claudeEvent {