feat: nsenter privileged mode, clean shutdown handling

- Switch containerd bridge from ctr-run to nsenter: tcpdump runs as a
  child of the exec session and dies with the helper pod, eliminating
  orphaned container tasks
- Add watchTargetPod: auto-stop sniff on target pod deletion or terminal phase
- Treat exit 137/143 and context cancellation as clean stops (not errors)
- Suppress context-cancel noise in ExecuteCommand error log

ksniff v1.7.3

Bug fixes
  - Privileged mode: fix race that left orphaned tcpdump tasks on the
    node when wireshark or the helper script failed before cleanup
  - Validate wireshark presence in PATH before creating the privileged
    pod, so missing wireshark fails fast with a clear error
  - Suppress spurious 'failed to kill wireshark process' log on Windows
    when wireshark has already exited

Changes
  - Drop dependency on docker.io/maintained/tcpdump:latest. Both
    privileged and ephemeral modes now default to the project's own
    ksniff-tcpdump image (versioned per release via ldflags)

Dependencies
  - Bump golang.org/x/oauth2 to 0.27.0
  - Bump github.com/moby/spdystream to 0.5.1

goreleaser fix

Upgrade golangci-lint to v2; consolidate e2e workflows

- Migrate .golangci.yml to v2 format (linters-settings → linters.settings,
  formatters block, exclusion presets)
- Upgrade golangci-lint-action v6 → v9 to support Go 1.26
- Replace three separate e2e workflows (k3d, minikube-docker, minikube-crio)
  with a single e2e.yml that builds the tcpdump image once and fans out to
  all three test jobs in parallel — eliminates triple redundant image builds
- Add e2e badge to README

Fix image tag casing: lowercase owner dynamically, add GHA build cache

support Apple Silicon M1 (eldadru#133)

Co-authored-by: Weidong Feng <weidong.feng@shanbay.com>

GitHub Action for unit tests and e2e test on k3s/k3d and minikube (do…

…cker and cri-o). (eldadru#118)

Add known issues section and links to discussions in GH issues

Merge pull request eldadru#77 from bostrt/crio

Adding support for CRI-O and flexibility for more.

Merge pull request eldadru#68 from Harwayne/fix-tests

Update the unit tests to compile.