Add inbound header filtering to CXF and Knative filter strategies

[Croway]

Summary

• Align CxfRsHeaderFilterStrategy, CxfHeaderFilterStrategy and KnativeHttpHeaderFilterStrategy with HttpHeaderFilterStrategy by adding setInFilterStartsWith(CAMEL_FILTER_STARTS_WITH) so that internal headers are filtered in both directions.

Test plan

• mvn verify on camel-cxf-rest (42 tests passed)
• mvn verify on camel-cxf-transport (12 tests passed)
• mvn verify on camel-knative-http (162 tests passed)

[github-actions]

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[gnodet]

Nice work on this PR, Federico! The change is clean, well-scoped, and addresses a legitimate gap in header filtering by aligning these three filter strategies with HttpHeaderFilterStrategy.

A few observations:

JIRA linkage

This appears related to CAMEL-23222 ("Filter inbound Camel headers") — a similar setInFilterStartsWith was added to MailHeaderFilterStrategy under that ticket. If this is part of the same effort, linking the JIRA would provide traceability. I can create a dedicated JIRA issue if needed.

Inbound/outbound asymmetry in KnativeHttpHeaderFilterStrategy

The outbound filter uses a regex (?i)(Camel|org\.apache\.camel)[…] which catches both Camel and org.apache.camel prefixes, while the new inbound filter uses CAMEL_FILTER_STARTS_WITH ({"Camel", "camel"}) which doesn't cover org.apache.camel-prefixed headers. This is consistent with how HttpHeaderFilterStrategy does it, so the alignment goal is met — just flagging it for awareness.

Tests

The PR description mentions existing module tests pass, which is good. However, there are no new tests that specifically verify that Camel-prefixed headers are filtered on the inbound path. A test asserting that a header like CamelFileName is stripped when coming from an external source would strengthen confidence and prevent regressions. I can help provide those tests if you'd like.

Overall, this looks good — the suggestions above are non-blocking.

Claude Code on behalf of Guillaume Nodet