swarmexec v1.6.0 — log filtering, service inspect & editing, client logging

logs:
- format-aware parsing + filtering (classic/json/gelf/raw, min-level, grep)
  in the `logs` command and the TUI log view (live re-filter, format/level
  cycling, message grep).
- `logs -f` follows a service across container replacement (rolling update /
  restart / reschedule), like `docker service logs -f`.
- log view: toggle mouse capture for terminal select/copy.

ui:
- configurable shortcut keys via keys.yaml.
- Networks tab: networks colour-coded by type; attach/detach a service to a
  network. Secrets: attach/detach a service to a secret (autocomplete).
- inspect (`i`): tabular, operator-first view + raw-JSON toggle, with
  individually selectable/copyable lines. On a service it also edits via
  ServiceUpdate: scale, ports, labels and networks (staged editors).
- single adaptive bottom footer describing the active view's keys.
- the container tree auto-refreshes so background changes appear without `r`.

client:
- structured logging (slog) to a file and an in-memory ring, a toggleable
  in-TUI log viewer, and a responsiveness watchdog; container list refreshes
  off the UI goroutine so the TUI no longer stalls.