fix(gateway): classify email document attachments as DOCUMENT

Email cached document attachments and placed them in media_urls, but
msg_type only flipped on image attachments — documents stayed TEXT and
run.py's document-context injection (gated on MessageType.DOCUMENT)
silently dropped them. Same bug class as Signal #12845. DOCUMENT wins
over PHOTO for mixed attachments since image handling keys off per-path
mime types while document injection gates strictly on message_type.

gateway/platforms/email.py

@@ -470,8 +470,15 @@ class EmailAdapter(BasePlatformAdapter):
         for att in attachments:
             media_urls.append(att["path"])
             media_types.append(att["media_type"])
-            if att["type"] == "image":
+            if att["type"] == "image" and msg_type == MessageType.TEXT:
                 msg_type = MessageType.PHOTO
+            elif att["type"] == "document":
+                # Document wins over PHOTO for mixed attachments: run.py's
+                # image handling keys off the per-path image/* mime type
+                # regardless of message_type, but document-context injection
+                # gates strictly on MessageType.DOCUMENT — so DOCUMENT is the
+                # only classification that surfaces both.
+                msg_type = MessageType.DOCUMENT
 
         # Store thread context for reply threading
         self._thread_context[sender_addr] = {

tests/gateway/test_email.py

@@ -393,6 +393,68 @@ class TestDispatchMessage(unittest.TestCase):
         self.assertEqual(captured_events[0].message_type, MessageType.PHOTO)
         self.assertEqual(captured_events[0].media_urls, ["/tmp/img.jpg"])
 
+    def test_document_attachment_sets_document_type(self):
+        """Email with a document attachment must set DOCUMENT so run.py injects file context."""
+        import asyncio
+        from gateway.platforms.base import MessageType
+        adapter = self._make_adapter()
+        captured_events = []
+
+        async def capture_handle(event):
+            captured_events.append(event)
+
+        adapter.handle_message = capture_handle
+
+        msg_data = {
+            "uid": b"6",
+            "sender_addr": "user@test.com",
+            "sender_name": "User",
+            "subject": "Re: report",
+            "message_id": "<msg6@test.com>",
+            "in_reply_to": "",
+            "body": "See attached",
+            "attachments": [{"path": "/tmp/report.pdf", "filename": "report.pdf", "type": "document", "media_type": "application/pdf"}],
+            "date": "",
+        }
+
+        asyncio.run(adapter._dispatch_message(msg_data))
+        self.assertEqual(len(captured_events), 1)
+        self.assertEqual(captured_events[0].message_type, MessageType.DOCUMENT)
+        self.assertEqual(captured_events[0].media_urls, ["/tmp/report.pdf"])
+
+    def test_mixed_image_and_document_prefers_document(self):
+        """DOCUMENT wins for mixed attachments — image handling keys off per-path
+        mime types, but document injection gates strictly on MessageType.DOCUMENT."""
+        import asyncio
+        from gateway.platforms.base import MessageType
+        adapter = self._make_adapter()
+        captured_events = []
+
+        async def capture_handle(event):
+            captured_events.append(event)
+
+        adapter.handle_message = capture_handle
+
+        msg_data = {
+            "uid": b"7",
+            "sender_addr": "user@test.com",
+            "sender_name": "User",
+            "subject": "Re: both",
+            "message_id": "<msg7@test.com>",
+            "in_reply_to": "",
+            "body": "Photo and PDF",
+            "attachments": [
+                {"path": "/tmp/img.jpg", "filename": "img.jpg", "type": "image", "media_type": "image/jpeg"},
+                {"path": "/tmp/report.pdf", "filename": "report.pdf", "type": "document", "media_type": "application/pdf"},
+            ],
+            "date": "",
+        }
+
+        asyncio.run(adapter._dispatch_message(msg_data))
+        self.assertEqual(len(captured_events), 1)
+        self.assertEqual(captured_events[0].message_type, MessageType.DOCUMENT)
+        self.assertEqual(len(captured_events[0].media_urls), 2)
+
     def test_source_built_correctly(self):
         """Session source should have correct chat_id and user info."""
         import asyncio