What

• Add a custom Response.__repr__ that summarizes the body as a byte count.

Why

• Response is a @dataclass with a content: bytes field, so the auto-generated repr dumps the entire response body. Logging or printing a fetch result against a real endpoint floods the console with raw bytes.

How (brief)

• src/pythonnative/net.py: define Response.__repr__ returning Response(status=..., url=..., ok=..., content=<n> bytes). Uses type(self).__name__ so a subclass reprs with its own name.
• tests/test_net.py: add test_repr_summarizes_body (uses the existing echo-server fixture) asserting the repr contains the status and byte count but not the decoded body.

Testing

• ./scripts/check.sh passes.

Risks/Impact

• Changes the repr string only. No effect on status, url, headers, content, or any method. Response is not equality-compared anywhere (dataclass eq still auto-generated).

Docs/Follow-ups

• None.

Closes #43