fix(exit-node): preserve raw exit-node responses

Return raw exit-node responses from Apps Script when requested and strip stale exit-node content-encoding headers after server-side decompression.

assets/apps_script/Code.gs

@@ -202,6 +202,15 @@ function _doSingle(req) {
   try {
     var opts = _buildOpts(req);
     var resp = UrlFetchApp.fetch(req.u, opts);
+
+    // Raw-return mode for exit-node path.
+    // r:true = return destination body verbatim so Rust gets {s,h,b} unwrapped.
+    if (req.r === true) {
+      return ContentService
+        .createTextOutput(resp.getContentText())
+        .setMimeType(ContentService.MimeType.JSON);
+    }
+
     return _json({
       s: resp.getResponseCode(),
       h: _respHeaders(resp),
@@ -307,7 +316,7 @@ function _buildOpts(req) {
   var opts = {
     method: (req.m || "GET").toLowerCase(),
     muteHttpExceptions: true,
-    followRedirects: req.r !== false,
+    followRedirects: true,          // ← always true; r flag now has different meaning
     validateHttpsCertificates: true,
     escaping: false,
   };