async_update_interfaces does not report whether the requested interfaces were bound #1916

Problem

Zeroconf.async_update_interfaces is best-effort and returns None, so a caller cannot tell whether the requested configuration was applied.

Two failure paths are logged and swallowed:

• A listen socket rebuild that fails, for example switching an IPv4 instance to IPVersion.All on a host that cannot open a dual-stack AF_INET6 socket. The engine logs Skipping interface update; listen socket rebuild failed and returns False.
• A requested interface that fails to bind. The engine logs Interface ... not added once and carries on.

In both cases Zeroconf.async_update_interfaces still commits the requested interfaces and ip_version as the retained configuration, and returns normally.

Where

• Engine rebuild failure returns False, the same value as "nothing was added".
• _async_add_interface returns False for an interface that did not come up.
• Zeroconf.async_update_interfaces uses the engine's result only to decide whether to re-announce.

Why it matters

A caller that asks for dual-stack and cannot get it has no signal to fall back to IPVersion.V4Only, or to retry later. It also cannot log an accurate outcome: a caller that logs "reconciled with IPVersion.All" after a swallowed rebuild failure is wrong.

In esphome/device-builder#2864 this meant a runtime IPv4-only fallback could not be implemented, because the failure it would react to never surfaces.

Suggested fix

Report the outcome from the public method. Options:

• Return whether the desired interface set fully bound, or the list of interfaces that were skipped.
• Raise when the address family rebuild fails, since in that case none of the requested change was applied.

Either keeps the best-effort behaviour for per-interface failures while letting callers react.