[2748109647]

Summary

• Add an optional ServerSocketFactory to HTTPListenerConfiguration and use it to create the listener socket.
• Preserve the existing default plain-socket and certificate-backed TLS paths when no custom factory is configured.
• Use the listener's explicit TLS flag for the generated request scheme, so custom TLS sockets are represented as HTTPS.
• Add tests covering custom factory selection for both plain and TLS listeners.

Fixes #52

Verification

• mvn -B -ntp '-Dtest=HTTPServerThreadTest' test — 2 passed, 0 failures/errors.
• git diff --check — passed.
• mvn -B -ntp clean test — compiled all sources and ran 2,623 tests; 14 failures occurred in existing Windows-sensitive multipart/form-data tests. The unmodified main branch reproduced the same failure modes: invalid : characters in generated test log paths and local socket resets. The targeted factory tests pass. Linux CI has not yet run.