feat(proc): add cross-platform process and port inspection tool

[nooscraft]

Summary

• Adds ut proc with six subcommands: list, name, pid, port, ports, and kill
• Port-to-process mapping works natively on Linux (/proc/net/tcp), macOS (lsof), and Windows (netstat) with no extra dependencies beyond sysinfo
• kill sends SIGTERM by default (graceful) or SIGKILL with --force; on Windows both map to a hard kill
• list and ports render as proper columnar tables; all commands support --json for machine-readable output
• Duplicate (port, pid) entries, caused by processes binding both IPv4 and IPv6, are deduplicated

Changes

• src/tools/proc.rs — new tool
• src/tool.rs — new Output::Table variant that renders a JSON array as a columnar table in human mode and as JSON with --json
• Cargo.toml — adds sysinfo v0.39, enables preserve_order on serde_json so table column order is deterministic
• README.md — documents the new tool

Test plan

• ut proc list renders a columnar table
• ut proc list --name node --cmd shows full command line as extra column
• ut proc list --name node shows no cmd column without the flag
• ut proc pid $$ returns details for the current shell
• ut proc ports shows no duplicate rows
• ut proc port <port> finds the owning process (start ut serve --port 9999 first)
• ut proc port <unused> returns a clear error
• ut proc kill --port <port> terminates the process (start ut serve --port 9999 first)
• ut proc kill --pid <pid> terminates by PID
• ut --json proc list returns a valid JSON array
• cargo test proc passes all 8 tests