feat: add image upload support for post/reply/quote commands

- Add upload_media() method to TwitterClient (INIT/APPEND/FINALIZE flow
  via upload.twitter.com, supports JPEG/PNG/GIF/WebP up to 5MB)
- Extend create_tweet() and quote_tweet() with optional media_ids param
- Add --image/-i option to post, reply, and quote CLI commands (max 4)
- Add MediaUploadError exception for upload-specific error handling
- Add 6 unit tests covering upload flow, validation, and media_ids

Co-Authored-By: Catafal <67582323+Catafal@users.noreply.github.com>

tests/test_cli.py

@@ -321,7 +321,7 @@ def test_cli_reply_command(monkeypatch) -> None:
     calls = []
 
     class FakeClient:
-        def create_tweet(self, text: str, reply_to_id=None) -> str:
+        def create_tweet(self, text: str, reply_to_id=None, media_ids=None) -> str:
             calls.append({"text": text, "reply_to_id": reply_to_id})
             return "999"
 
@@ -338,7 +338,7 @@ def test_cli_quote_command(monkeypatch) -> None:
     calls = []
 
     class FakeClient:
-        def quote_tweet(self, tweet_id: str, text: str) -> str:
+        def quote_tweet(self, tweet_id: str, text: str, media_ids=None) -> str:
             calls.append({"tweet_id": tweet_id, "text": text})
             return "888"
 
@@ -353,7 +353,7 @@ def test_cli_quote_command(monkeypatch) -> None:
 
 def test_cli_post_json_output(monkeypatch) -> None:
     class FakeClient:
-        def create_tweet(self, text: str, reply_to_id=None) -> str:
+        def create_tweet(self, text: str, reply_to_id=None, media_ids=None) -> str:
             assert text == "hello"
             assert reply_to_id is None
             return "999"