iOS: Add poll support, fix contact name resolution, fix typos

- Add poll message decoding for iOS (ZMESSAGETYPE 46) using raw protobuf
  parsing of ZWAMESSAGEINFO.ZRECEIPTINFO blobs (no external dependency).
  Polls render with vote tallies and voter names in the HTML export.
- Fix iOS contact name resolution: pull ZFULLNAME from address book,
  resolve LID-based group members, fall back to ZWAPROFILEPUSHNAME,
  and avoid overwriting real names with phone numbers.
- Fix typo: 'expoter' -> 'exporter' in android_crypt.py and __main__.py.
- Add poll field to Message data model and update test fixtures.

Whatsapp_Chat_Exporter/data_model.py

@@ -361,6 +361,7 @@ class Message:
         self.thumb = None  # Android specific
         self.sticker = False
         self.reactions = {}
+        self.poll = None
 
     def to_json(self) -> Dict[str, Any]:
         """Convert message to JSON-serializable dict."""