Virtualize broker TCP ports

[Weidong Cui (wdcui)]

This PR gives each broker session an independent guest TCP port namespace, keeps Linux backend endpoints private, and translates session-local TCP connections and accepted peer addresses.

It also establishes the portable TCP publication split: broker core owns publication declarations, reserved guest ports, cross-session claim ownership, monotonic listener generations, and RAII release; the Linux platform owns external endpoint reservation, descriptor realization, epoll integration, stale-connection draining, and tuple translation. Exact claim tokens are retained through listen rollback and teardown so stale generations cannot detach newer listeners.

Production configuration now builds core TcpPortPublication declarations and passes them to LinuxSocketProvider::new_with_tcp_port_publications; UDP remains directly host-backed and the broker protocol version is unchanged.

[github-actions]

🤖 SemverChecks 🤖 ⚠️ Potential breaking API changes detected ⚠️

Click for details

--- failure struct_pub_field_missing: pub struct's pub field removed or renamed ---

Description:
A publicly-visible struct has at least one public field that is no longer available under its prior name. It may have been renamed or removed entirely.
        ref: https://doc.rust-lang.org/cargo/reference/semver.html#item-remove
       impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.50.0/src/lints/struct_pub_field_missing.ron

Failed in:
  field local_address of struct AcceptedPlatformSocket, previously in file /home/runner/work/litebox/litebox/target/semver-checks/git-ulitebox/7a63b6de36d1f08d757b72103b15801cf997c8a2/litebox_broker_core/src/socket.rs:31

--- failure trait_method_parameter_count_changed: pub trait method parameter count changed ---

Description:
A trait method now takes a different number of parameters.
        ref: https://doc.rust-lang.org/cargo/reference/semver.html#trait-item-signature
       impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.50.0/src/lints/trait_method_parameter_count_changed.ron

Failed in:
  PlatformSocket::listen now takes 2 instead of 1 parameters, in file /home/runner/work/litebox/litebox/litebox_broker_core/src/socket.rs:364

--- failure method_parameter_count_changed: pub method parameter count changed ---

Description:
A publicly-visible method now takes a different number of parameters, not counting the receiver (self) parameter.
        ref: https://doc.rust-lang.org/cargo/reference/semver.html#fn-change-arity
       impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.50.0/src/lints/method_parameter_count_changed.ron

Failed in:
  litebox_broker_platform_linux_userland::LinuxSocketProvider::new takes 1 parameters in /home/runner/work/litebox/litebox/target/semver-checks/git-ulitebox/7a63b6de36d1f08d757b72103b15801cf997c8a2/litebox_broker_platform_linux_userland/src/socket.rs:58, but now takes 2 parameters in /home/runner/work/litebox/litebox/litebox_broker_platform_linux_userland/src/socket.rs:76