Added full support for the Bot API 9.6 (#1792)

* Added full support for the Bot API 9.6

* Add support for `managed_bot` updates

* Set `description_parse_mode` default to `"parse_mode"` and use `DateTime` for `addition_date` in `PollOption`

* Update changelog with features and changes from Bot API 9.6

* Add changelog fragment generator and update poll parameter descriptions

.serena/memories/testing_patterns.md

@@ -0,0 +1,45 @@
+# Testing Patterns
+
+## Framework
+- pytest with async support
+- No `pytest-asyncio` explicit marks needed (configured globally in pyproject.toml)
+- `MockedBot` (tests/mocked_bot.py) — use for all bot method tests, no real HTTP
+
+## MockedBot pattern
+```python
+from tests.mocked_bot import MockedBot
+from aiogram.methods import SendMessage
+from aiogram.types import Message, Chat
+import datetime
+
+class TestSendMessage:
+    async def test_bot_method(self, bot: MockedBot):
+        prepare_result = bot.add_result_for(
+            SendMessage,
+            ok=True,
+            result=Message(
+                message_id=42,
+                date=datetime.datetime.now(),
+                text="test",
+                chat=Chat(id=42, type="private"),
+            ),
+        )
+        response: Message = await bot.send_message(chat_id=42, text="test")
+        bot.get_request()
+        assert response == prepare_result.result
+```
+
+## Test structure
+- Class per type/method: `class TestSendMessage:`
+- One test per scenario: `async def test_<scenario>(self, ...)`
+- `bot` fixture comes from `tests/conftest.py`
+
+## Integration tests
+- Redis: `uv run pytest --redis redis://localhost:6379/0 tests`
+- MongoDB: `uv run pytest --mongo mongodb://mongo:mongo@localhost:27017 tests`
+- Only run these when Redis/Mongo storage code is affected
+
+## What NOT to do
+- Do not mock the database/storage in FSM tests — use real backends or memory storage
+- Do not introduce new test dependencies for small tests
+- Keep test style consistent with existing suite