Add VirtualPipe support to InodeValFilePollGuard

VirtualPipeTx and VirtualPipeRx were not handled in InodeValFilePollGuard::new(),
causing poll_oneoff to return Errno::Badf when polling on VirtualPipe fds.

Since VirtualPipe types implement VirtualFile, they can use the existing File
poll guard mode.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: NathanFlurry

lib/wasix/src/fs/inode_guard.rs

@@ -67,6 +67,9 @@ impl InodeValFilePollGuard {
             Kind::DuplexPipe { pipe } => InodeValFilePollGuardMode::DuplexPipe {
                 pipe: Arc::new(RwLock::new(Box::new(pipe.clone()))),
             },
+            // VirtualPipe types are VirtualFile implementations, so use File mode
+            Kind::VirtualPipeTx { tx } => InodeValFilePollGuardMode::File(tx.clone()),
+            Kind::VirtualPipeRx { rx } => InodeValFilePollGuardMode::File(rx.clone()),
             _ => {
                 return None;
             }