Add per-user browser session duration controls

[bifrost0x]

Summary

• add a bounded per-user duration for normal browser sign-ins under Settings → Preferences
• retain the current 30-minute default and offer explicit 1, 2, 4, and 8-hour choices
• explain that browser authentication expiry is independent of SSH idle timeout and applies from the next sign-in
• keep the separate seven-day "Remember me" behavior unchanged

Background

Discussion #201 exposed a deterministic disconnect after roughly 30 minutes. The authentication hardening introduced an absolute server-side browser-session expiry, and subsequent Socket.IO enforcement correctly rejected even the keep-alive event once that authentication record expired. The fail-closed behavior was intentional, but the fixed default and its relationship to an active SSH session were not visible to users.

Security properties

• 30 minutes remains the default
• the server accepts only an exact allowlist of durations, with an 8-hour maximum
• there is no unlimited or sliding-expiration option
• authentication-session records, account-generation checks, ownership enforcement, and revocation on logout, account lock, or deletion remain intact
• Flask's signed cookie window is only an outer 8-hour ceiling; the per-user server-side authentication record remains authoritative
• invalid or corrupt preference data falls back to the secure 30-minute default

Validation

• pytest -q: 2,387 passed and 29 skipped
• focused authentication, preferences, UI, shell, i18n, static-delivery, and documentation tests passed
• JavaScript tests: 39 passed
• Playwright settings and management regression tests: 8 passed
• ESLint and git diff --check passed

Related: #201

[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 2026-09-06T13:04:08.241771Z	1b7e196	Manual request

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[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 72a996cd60

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[bifrost0x]

@codex review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. You're on a roll.

Reviewed commit: 1b7e19606a

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