fix(autocomplete): omit hidden flags from suggestions

[sylvesterkaczmarek]

Summary

Keep hidden/internal CLI flags out of shell-completion suggestions.

Problem

The autocomplete code already respects cli.VisibleFlag when resolving an entered flag through findFlag, but the flag-name completion path loops over every flag in cmd.Flags without applying the same visibility check.

That means flags deliberately marked hidden can still be surfaced by Bash/Zsh/Fish/PowerShell completion when the user starts typing - or --.

This is separate from the existing hidden-command work: command suggestions already have their own child.Hidden handling, while this PR fixes flag visibility.

Fix

Apply the same cli.VisibleFlag / IsVisible() guard used by findFlag before generating flag-name completions.

Visible flags and aliases keep their existing completion behavior. Flags that do not implement cli.VisibleFlag are also unchanged.

Regression coverage

Added a focused synthetic-command regression with one visible and one hidden flag, each with a short alias. The test verifies both long and short visible names remain suggested while both hidden names are omitted.

Validation

The branch is based directly on current upstream main (a7719136b8ed401b0c51a05553a5e4f720150307) and contains one DCO-signed commit. The production change is 3 lines in handwritten internal/autocomplete/autocomplete.go, plus focused regression coverage. Full repository test execution is left to CI.

Risk

Low. The change only removes completion candidates for flags the CLI already marks as not visible; parsing and command execution are unchanged.

[markstuart-oai]

@codex review

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-06T01:31:55.546309Z	7aba6a2	Manual request
🔒 Security Review	✅ Completed 2026-09-06T01:33:55.063606Z	7aba6a2	Manual request

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Codex Review: Didn't find any major issues. Can't wait for the next one!

Reviewed commit: 7aba6a28ee

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Security review completed. No security issues were found in this pull request.

Reviewed commit: 7aba6a28ee

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