fix(cli): hide completion command from top-level help (closes #39)

[raptor7197]

What

hides the completion command from top-level help. the command itself and all four shell generators are unchanged.

Why

Fixes #39

pr #55 shipped the feature but missed the last acceptance criterion: "hidden from the top-level help by default". the command is plumbing, not a user-facing feature.

How

single-line change: set Hidden: true on the cobra command. hidden commands stay fully functional and keep generating valid scripts. no new tests needed; existing TestCompletionCmd covers all four shells.

Testing

• go build ./... passes

• go test ./internal/cli/ passes (full go test ./... not run locally, no docker for integration tests)

• go vet ./... passes

• golangci-lint run ./... passes

• tested locally with: /tmp/kerno --help | grep -i completion (0 matches), /tmp/kerno completion bash | bash -n, zsh -n, fish --no-execute, and __complete do / __complete doctor --output '' return correct suggestions

• N/A - pure docs/refactor

Checklist

• PR title follows Conventional Commits (fix(cli): hide completion command from top-level help)
• All commits are DCO-signed (git commit -s)
• No unrelated changes pulled in
• Documentation updated where user-visible behavior changed (n/a — no user-visible behavior beyond help output; readme already documents the command)
• Added/updated tests for new code paths (n/a — existing tests cover the command; hiding only affects help rendering)
• If a new doctor rule, paired with a chaos scenario in scripts/verify.sh (n/a)

[github-actions]

🚀 First PR — welcome aboard!

A few things to expect:

1. CI: every PR runs build + race tests + lint + (eventually) the kernel matrix. If something fails, the log will tell you exactly which gate.
2. DCO: every commit needs Signed-off-by: — git commit -s adds it automatically.
3. Conventional Commits: PR titles like feat(doctor): add new rule or fix(bpf): handle X. We squash-merge by default.
4. Review: a maintainer will review within 72 hours. Suggestions are conversations, not orders — push back if something doesn't fit your context.

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