Added read/write timeout support to Rust TTcpChannel

[ShemShadrack]

Summary

Add timeout configuration support to the Rust TTcpChannel.

This change adds:

• set_read_timeout
• set_write_timeout
• set_timeouts

Timeouts are applied immediately when the channel already wraps an open
TcpStream, and cached for later application when the channel is opened
after configuration.

Testing

Verified with:

• cargo fmt --manifest-path lib/rs/Cargo.toml --all -- --check
• cargo test --manifest-path lib/rs/Cargo.toml

Added unit tests covering:

• setting timeouts before open()
• applying cached timeouts during open()
• setting timeouts on wrapped streams
• clearing timeouts