concore_cli: add watch command for live simulation monitoring

[avinxshKD]

closes #449

added concore watch <study_dir> to the CLI, polls the edge/port directories every N seconds and shows a live table of simtime, current values, and write age per port. without this you had to cat files manually to see what a running simulation was doing.

new file only (watch.py). two-line additions to cli.py and init.py. no runtime code touched.

concore watch ./study_out          # live, refreshes every 2s
concore watch ./study_out --once   # single snapshot, exits
concore watch ./study_out -n 1     # faster refresh

[avinxshKD]

Hey @pradeeban kept it exactly as you wanted. new file only (watch.py), two lines added to the existing cli files, zero runtime changes.

one thing i noticed while building this, that edge dirs don't carry any metadata about which node wrote them last, so "active edges" is approximated by file mtime. There's actually a cleaner way to get this without any runtime changes: each node dir already has out1, out2 junctions pointing to the edge dirs (set up by build). Following those would let watch figure out which node owns which edge purely from the build structure, no new files needed. flagging for a future iteration, happy to pick it up if you think it's worth doing.