fix(backend): weekly score window spans 8 days instead of the documented 7 (off-by-one)

[arhxam]

Problem

get_scores() (database/action_items.py) documents its weekly window as "tasks created in the 7 days ending on that date", but builds it a day too wide:

day_start  = day
day_end    = day + timedelta(days=1)
week_start = day - timedelta(days=7)
...
weekly_q = col.where(FieldFilter('created_at', '>=', week_start)).where(FieldFilter('created_at', '<', day_end))

created_at ∈ [day-7, day+1) spans 8 calendar days (day-7 … day inclusive). So every task created on the day-7 date is pulled into the weekly totals, inflating weekly.total_tasks and skewing weekly.score.

Root cause

The adjacent daily window is built as [day, day+1) — exactly one day. That establishes the intended construction: an N-day window ending on day is [day-(N-1), day+1). For the 7-day weekly window that is [day-6, day+1), but the code uses day-7.

Concrete: for date="2026-07-19", the query lower bound is 2026-07-12T00:00Z, so a task created 2026-07-12 is counted — even though "7 days ending 2026-07-19" is 2026-07-13 … 2026-07-19.

Fix

-week_start = day - timedelta(days=7)
+week_start = day - timedelta(days=6)

This preserves the created_at field choice — the "matches Rust backend which uses created_at" comment is about the field, not the window size, and the Rust backend (desktop/macos/Backend-Rust) has no weekly-score window at all — and only corrects the span from 8 days to 7.

Tests

The existing get_scores coverage (test_desktop_migration.py::TestScoreComputation) only asserted the weekly query uses the created_at field, never the window bounds. Added test_weekly_window_spans_seven_days_ending_on_date, which captures the FieldFilter calls and asserts the created_at >= lower bound for date=2026-07-19 is 2026-07-13 (day-6), not 2026-07-12 (day-7).

Verification

Exercised the real get_scores with a mocked db + a FieldFilter tracker:

fixed:    created_at >= 2026-07-13T00:00Z   (window spans 7 days)
reverted: created_at >= 2026-07-12T00:00Z   (window spans 8 days) -> new assertion fails

black --line-length 120 --check database/action_items.py tests/unit/test_desktop_migration.py → clean.

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🤖 Generated with Claude Code

[Git-on-my-level]

Thanks for the focused fix — this looks like the right direction.

I reviewed the weekly score window change and the added regression coverage. The previous [day-7, day+1) range did span 8 calendar days for a "7 days ending on that date" window, and changing the lower bound to day - timedelta(days=6) makes the query match the documented inclusive 7-day window. The new test also checks the actual created_at >= bound, which covers the off-by-one rather than only checking the queried field.

I did not find a blocking code issue in this diff. Because this touches backend action-item scoring/user-data logic and the author is a first-time contributor, I’m leaving this as a positive maintainer signal rather than a formal approval; a human maintainer should still do the final merge decision.

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by AI on behalf of David — if you need David’s attention urgently, please @Git-on-my-level and escalate with need human response.

[kodjima33]

Backend off-by-one fix (weekly score window 8→7 days) with test. Approve-only — no CI checks ran for contributor.