[Aathi-27]

What does this PR do?

Fixes TCP server startup failures caused by bracketed IPv6 bind addresses and mismatched socket families.

Master startup converts IPv6 interface addresses into ZeroMQ URI form, such as [::]. The TCP publisher previously tried to bind that bracketed address directly and failed, leaving its publish port closed.

The patch normalizes bind addresses and selects the socket family from the actual interface address for publisher, request-server and load-balancer sockets. Client connection paths retain their existing flag-based behavior.

Issue

Fixes #66567

Validation

• On 3008.x, all 82 tests in tests/pytests/unit/transport/test_tcp.py pass with the fix.
• Without the fix, five new tests fail and 77 pass.
• Live master startup and TCP/IPv6 test.ping were checked on master before this port, not on 3008.x.

Includes regression tests and changelog/66567.fixed.md.

[twangboy]

If this bug exists on 3008.x, please rebase this PR against 3008.x branch.

[Aathi-27]

The affected code is the same on 3008.x, so this change is now based on 3008.x and the PR base has been updated. The new unit tests fail on 3008.x without the fix and pass with it.

[Aathi-27]

The latest CI attempt fails only on test_cluster_ready_fires_on_restart_from_persisted_log across 15 functional ZeroMQ jobs. I also found this test failing with the same assertion on 3008.x in Debian 11 and Debian 13 jobs. Could a maintainer confirm whether this is a known branch failure and advise whether anything is needed from this PR?

[dwoz]

@Aathi-27 Yes, I had merged to conflicting PRs which broke the full test suite. This will be resolved soon. I think this PR will be good to go.

[Aathi-27]

Thanks for confirming. I'll leave this PR unchanged while the upstream test suite is fixed. Please let me know if anything is needed from my side.