feat: community scraping

[terencedignon]

This adds community endpoints (community_info, community_members, community_moderators, community_tweets + raw variants) and CLI flags.

I had to tweak the parser so community member responses with missing fields still parse cleanly.

To test, run examples/community_scraping.py

---

Example trimmed response:

{
    "id": 1501272736215322629,
    "id_str": "1501272736215322629",
    "name": "New York Mets",
    "description": "Your baseball source for all Mets news, updates, in-game highlights and content. For Mets fans by Mets fans #LGM",
    "memberCount": 27105,
    "moderatorCount": 0,
    "rules": [
      {"id_str": "1501272736383090692", "name": "Keep Tweets on topic.", "description": ""},
      {"id_str": "1521944352750280704", "name": "No Trolls", "description": ""},
      {"id_str": "1877106707501035784", "name": "No Politics", "description": ""},
      {"id_str": "1939637317636858332", "name": "No Hate Speech/Slurs", "description": "Ridiculous that this needed to be added. You will be banned"}
    ],
    "topicId": null,
    "topicName": "Baseball",
    "isNsfw": false
  }

And a typical member item from community_members:

  {
    "community_role": "Member",
    "rest_id": "1118575978169737217",
    "core": {"screen_name": "GottaBelievePod", "name": "We Gotta Believe"},
    "legacy": {...minimal legacy fields...}
  }

Closes #273.

[terencedignon]

gentle ping on this. Again, no worries if you think this is out of scope.