[zhanghao0806]

Description

Ignore unrelated Kafka header values when reading binary CloudEvents. Previously the reader decoded every header as UTF-8 before checking its name, so an application header such as correlation-bin: b'\xff\x00\xfe' prevented a valid event from being read.

Only ce_* and content-type values are decoded. Invalid UTF-8 in those CloudEvents headers still raises an error.

Fixes #306.

Validation

• Regression before the fix: 2 failed, 54 passed in the Kafka binding tests.
• Complete pytest -q: 879 passed, 18 xfailed.
• Ruff lint/format, source MyPy, and git diff --check: passed.
• MyPy including the existing Kafka test file reports the same six pre-existing errors on the base and patched versions; these are outside the added tests.
• Tests exercise both from_binary and from_kafka; no live broker required or used.

Prepared with AI assistance; commits are signed off.

[PlugaruT]

Code LGTM. Thanks