feat: add combined logs command

[galargh]

Related to #126

This PR adds foc-devnet logs to print combined logs from all containers in the active devnet run.

It supports --follow / -f and --tail / -t flags, similar to docker logs for example, for live log tailing (the latter can only be supplied if follow mode is on; it prints N lines per-container before starting the follow). Each line in the output is prefixed with timestamp and container name for easier cross-service debugging.

Details

• Finite mode uses docker logs --timestamps, merges entries from all current-run containers, and sorts by timestamp.
• Follow mode starts one docker logs --follow stream per current-run container and prefixes output as it arrives.
• Container selection is restricted to the current run ID prefix, avoiding logs from old runs or unrelated foc-* containers.

Testing

• cargo fmt --check
• cargo test
• cargo run -- logs --help
• FIX=0 ./scripts/lint.sh

I also run a tiny smoke test:

1. Set FOC_DEVNET_BASEDIR to a local ignored directory.

2. Write a fake current_runid.json with run ID 20260904T1200_LogSmoke.

3. Start two simple Docker containers named with that run prefix:

   • foc-20260904T1200_LogSmoke-log-smoke-1
   • foc-20260904T1200_LogSmoke-log-smoke-2

   *Each container prints one stdout and one stderr line every second.

4. Run cargo run -- logs --follow --tail 5 which discovers those containers by current run ID prefix and follows their logs.

Result:

...
2026-09-04T22:39:45.448834377Z foc-20260904T1200_LogSmoke-log-smoke-2 | smoke-2 stderr 310
2026-09-04T22:39:46.328370977Z foc-20260904T1200_LogSmoke-log-smoke-1 | smoke-1 stdout 311
2026-09-04T22:39:46.328365227Z foc-20260904T1200_LogSmoke-log-smoke-1 | smoke-1 stderr 311
2026-09-04T22:39:46.452703026Z foc-20260904T1200_LogSmoke-log-smoke-2 | smoke-2 stderr 311
2026-09-04T22:39:46.452682067Z foc-20260904T1200_LogSmoke-log-smoke-2 | smoke-2 stdout 311
2026-09-04T22:39:47.336456973Z foc-20260904T1200_LogSmoke-log-smoke-1 | smoke-1 stdout 312
2026-09-04T22:39:47.335890583Z foc-20260904T1200_LogSmoke-log-smoke-1 | smoke-1 stderr 312
2026-09-04T22:39:47.457986144Z foc-20260904T1200_LogSmoke-log-smoke-2 | smoke-2 stdout 312
2026-09-04T22:39:47.457986185Z foc-20260904T1200_LogSmoke-log-smoke-2 | smoke-2 stderr 312
...