Fix outputSpecsV2: file_to_tercen returns .content not documentId

file_to_tercen() returns: filename, mimetype, .content

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: amaurel

operator.json

@@ -309,7 +309,7 @@
               "attributes": [
                 {
                   "kind": "Attribute",
-                  "name": "documentId",
+                  "name": "filename",
                   "type": "string"
                 },
                 {
@@ -319,7 +319,7 @@
                 },
                 {
                   "kind": "Attribute",
-                  "name": "filename",
+                  "name": ".content",
                   "type": "string"
                 }
               ]