fix: hour metric period returns datetimes

[ashenfad]

No description provided.

[Copilot]

Pull request overview

This PR adds support for hourly period aggregation to metric functions, with datetime-labeled keys instead of date keys for hour periods.

• Adds "hour" as a valid period option for metric functions
• Returns datetime keys for hourly periods (instead of date keys used by other periods)
• Updates documentation to clarify return type variations based on period and group_by parameters

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
docs/API.md	Documents the new "hour" period option and explains how return key types vary by period/group_by
calgebra/metrics.py	Updates _period_windows to return datetime labels for hourly periods while keeping date labels for other periods
calgebra/docs/API.md	Duplicate documentation update (identical to docs/API.md)

Comments suppressed due to low confidence (1)

calgebra/metrics.py:128

• The conversion logic on line 126 checks isinstance(dt, datetime) even though _period_windows_with_dt always returns datetime objects for all periods. This conditional is unnecessary and can be simplified to always call .date() for non-hourly periods.

    if period == "hour":
        return [(dt, ws, we) for dt, ws, we in windows]
    return [
        (dt.date() if isinstance(dt, datetime) else dt, ws, we)
        for dt, ws, we in windows
    ]

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