Pipe bind has no retry — stale handles cause silent fallthrough

[kKaskak]

At main.rs:172-191, pipe bind is attempted once with no retry. A stale pipe handle from a not-fully-cleaned-up previous instance can cause ERROR_ACCESS_DENIED. The forward path has a 25-retry loop but the bind path doesn't. Should retry bind similarly.

[kKaskak]

Verdict: valid.

Reviewed against current main: the bind path still makes one PipeServer::bind attempt through app.rs and named_pipe.rs, and silently disables IPC if it fails. There is no retry or fallback, so a stale first pipe instance or transient CreateNamedPipeW failure leaves a running shell that later launches cannot forward to. Add bounded retry and log/report final failure.