fix(sandbox): make peer-binary resolution netns-robust

[laitingsheng]

Summary

Peer-binary resolution scanned only /proc/<entrypoint_pid>/net/tcp{,6} to find the socket inode for a TCP peer. If entrypoint_pid was stale (process exited, PID recycled) or sat in a different netns than the one actually carrying the connection — which is what happens in nested-container setups like macOS Docker Desktop with k3s — the scan returned "No ESTABLISHED TCP connection found" and the proxy denied the request with binary=-. Add a (local_port, remote_port) filter and a netns-deduped /proc walk fallback so the inode is found wherever the connection actually lives.

Related Issue

Fixes NVIDIA/NemoClaw#1471.

Changes

• crates/openshell-sandbox/src/procfs.rs: parse_proc_net_tcp now matches connections by both local_port == peer_port and rem_port == remote_port. On primary-PID miss, walk /proc, dedup by the netns inode of each PID via stat /proc/<pid>/ns/net, and scan one /proc/<pid>/net/tcp per distinct netns. Socket inodes are kernel-global, so a match found in any netns resolves to the correct FD-holding processes downstream. New helpers scan_pid_net_tcp and parse_hex_port.
• crates/openshell-sandbox/src/proxy.rs: stop dropping client.local_addr() on the floor — thread the proxy's accepted local address through evaluate_opa_tcp → resolve_process_identity → resolve_tcp_peer_socket_owners, both for CONNECT and for forward-proxy paths.
• crates/openshell-sandbox/src/bypass_monitor.rs: pass the kmsg event's dst_port so bypass-attempt identity resolution uses the same filter.
• crates/openshell-sandbox/src/procfs.rs (tests): two new tests — one asserts the fallback walks /proc and finds the connection when entrypoint_pid is a PID that doesn't exist; the other asserts the remote-port filter rejects a stale match when only the local port collides.

Testing

• mise run pre-commit passes
• Unit tests added/updated
• E2E tests added/updated (if applicable)

Checklist

• Follows Conventional Commits
• Commits are signed off (DCO)
• Architecture docs updated (if applicable)

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