fix: strip time component in default base template date comparisons

[loukandr]

Problem

today() returns midnight in the Bases formula language, so day-level comparisons in tasks-default.base fail for any value with a time component. A task scheduled for today at a non-midnight time (e.g. 15:45) is excluded from the Today view because date(scheduled) == today() evaluates <today> 15:45 == <today> 00:00 → false. The same issue affects >= today() and <= today() + "Nd" checks across several formulas.

Reported in #1124.

Repro

1. Create a task with scheduled: 2027-01-15T15:45 (use today's date, any non-midnight time).
2. Open the Today view in tasks-default.base.
3. Task is missing.

Fix

Add .date() to strip the time component before comparing, matching the isDueToday and isScheduledToday formulas in the same file.

Affected:

• View filters: Today, This Week
• Formulas: isDueThisWeek, isThisWeek, dueDateCategory, nextDateCategory, dueDateDisplay

< today() comparisons (Overdue branches) are left as-is, they evaluate correctly without .date().

Tests

Extended tests/unit/templates/defaultBasesFiles.test.ts with positive pins for the affected formulas and negative matchers against the time-naive shapes.

Fixes #1124