Add PORT column to overmind status and --json flag

[bradgessler]

Summary

• Adds a PORT column to overmind status so you can see which port each process is assigned
• Adds a --json / -j flag to overmind status for machine-readable output

Why

External tools that work alongside overmind (reverse proxies, dev tooling, service discovery) currently have no way to ask overmind which ports its processes are running on. The ports are deterministic but require knowing the base port, step, and Procfile order to calculate — which is error-prone and duplicates logic.

Adding port info to status and a JSON output mode lets other tools introspect running services directly:

$ overmind status
PROCESS PORT      PID       STATUS
web     5000      37447     running
css     5100      37448     running

$ overmind status --json
[{"name":"web","port":5000,"pid":37447,"status":"running"},{"name":"css","port":5100,"pid":37448,"status":"running"}]

Implementation

• Stores the assigned port on the process struct (previously only available during init via procfileEntry)
• Adds PORT column to the existing status table output
• Adds status-json protocol command to the command center
• Adds --json / -j flag to the status CLI command

Test plan

• overmind status shows all processes with PORT, PID, and status
• overmind status --json returns valid JSON array
• overmind status -j shorthand works
• go build and go vet pass clean

🤖 Generated with Claude Code

[dinsley]

would be awesome to get this one merged, would help us improve some internal DX I've been eyeing.