Replace max sleep hours with earliest reasonable bedtime

[gsbernstein]

Summary

Replaces max sleep hours per night with earliest reasonable bedtime — a time-of-day picker that derives the longest allowed sleep window from wake time.

Also removes the minimum sleep hours setting. When you're ahead of your sleep goal, recommendations floor at your goal rather than encouraging a shorter night.

Schema

Clean UserPreferences model with only earliestReasonableBedtime (no legacy maxSleepHoursPerNight / minSleepHoursPerNight). All users are already on the new setting.

Changes

• UserPreferences — earliestReasonableBedtime + effectiveMaxSleepHours
• SettingsView — earliest bedtime picker with derived max-hours helper text
• ViewModel — drops min-sleep parameter; ahead-of-goal nights recommend at least the sleep goal
• ContentView — uses effectiveMaxSleepHours

Note

Separate from sleep insights (#14). If both land, wire effectiveMaxSleepHours into the insights engine in ContentView.

  

[Copilot]

Pull request overview

This PR replaces the “max sleep hours per night” limit with an “earliest reasonable bedtime” time picker, deriving the maximum allowed sleep window from the user’s wake time, and removes the minimum-sleep setting from the recommendation logic.

Changes:

• Introduces earliestReasonableBedtime in UserPreferences and derives effectiveMaxSleepHours from wake time.
• Updates Settings UI to use a time-of-day picker and display the derived maximum sleep window.
• Simplifies bedtime recommendation inputs by removing the min-sleep parameter and flooring “ahead” recommendations at the sleep goal.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
Bedtime/Bedtime/Views/SettingsView.swift	Replaces max/min sleep sliders with an earliest-bedtime picker and derived helper text.
Bedtime/Bedtime/Models/ViewModel.swift	Removes minSleepHours input and adjusts recommendation floor logic when ahead of goal.
Bedtime/Bedtime/Models/UserPreferences.swift	Removes legacy max/min fields; adds earliest bedtime and a derived max-sleep calculation helper.
Bedtime/Bedtime/ContentView.swift	Switches recommendation input from legacy max hours to effectiveMaxSleepHours.

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[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

Comments suppressed due to low confidence (1)

Bedtime/Bedtime/Models/ViewModel.swift:75

• Now that maxSleepHours is explicitly DST-aware, the bedtime calculation should also be anchored to the next actual wake date; subtracting from the stored wakeTime date (which is effectively just a time-of-day) won’t account for DST transitions and can be off by an hour on those nights.

            reason = "You're ahead of the game! Aim for at least \(String(format: "%.1f", sleepGoal)) hours tonight."
        }
        
        // Calculate recommended bedtime
        let recommendedBedtime = calendar.date(byAdding: .minute, value: -Int(totalSleepNeeded * 60), to: wakeTime) ?? wakeTime.addingTimeInterval(-totalSleepNeeded * 60 * 60)