TypeScript SDK: log socket buffering and reconnect hardening

[jason810496]

Background

The Java and Go SDK runtimes buffer logs while the log socket is not yet connected. The TypeScript coordinator runtime connects the log socket before runtime logs begin, which covers startup, but has no buffering for reconnect scenarios.

What needs to happen

1. Add log buffering to the TypeScript runtime's log channel so logs emitted while the socket is disconnected (including reconnects) are held and flushed once connected, matching the Java and Go implementations.

Acceptance criteria

• Logs emitted before connection or during a reconnect are not lost.

Context

• Review thread: Add TypeScript coordinator runtime #69079 (comment), deferred in Add TypeScript coordinator runtime #69079 (comment)