Rename air logs --lines to --tail

[caroline-db]

Changes

• Rename the experimental air logs --lines flag to --tail across the command, help text, validation, and tests.

Why

• --tail is the more conventional name and aligns with the Python AIR CLI.
• The Go CLI scaffolding was established before the Python CLI renamed this flag, so that later change was not carried into the Go implementation.

Tests

• ./task checks
• ./task test
• ./task build
• All Go lint modules and Ruff 0.15.17 formatting/lint checks

This PR was written with Codex.

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• PR number: 6592
• Commit SHA: f54481ee8cc60c6feba2cba9c7dc5d7ae4c877b8

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[github-actions]

Approval status: pending

/acceptance/experimental/air/ - needs approval

5 files changed
Suggested: @ben-hansen-db
Also eligible: @vinchenzo-db, @apeforest, @bfontain, @panchalhp-db, @maggiewang-db, @pardis-beikzadeh-db

/experimental/air/ - needs approval

4 files changed
Suggested: @ben-hansen-db
Also eligible: @vinchenzo-db, @apeforest, @bfontain, @panchalhp-db, @maggiewang-db, @pardis-beikzadeh-db

_{Any maintainer (@andrewnester, @anton-107, @denik, @pietern, @shreyas-goenka, @simonfaltum, @renaudhartert-db, @janniklasrose, @lennartkats-db, @rugpanov, @rclarey) can approve all areas.
See OWNERS for ownership rules.}