fix(widget): revert category grouping to top-level

[TimeToBuildBob]

Reverts the category-grouping change from #231, which regressed the homescreen widget in two ways reported in #142.

Problem

#231 (merged 2026-08-20) changed parseCategories() to group by the full category path ("Work > Programming") to match the Activity view. Two regressions resulted:

1. Full path is wrong for a widget — a widget should show top-level "Work" with all subcategories summed, not "Work > Programming" rows.
2. Inflated uncategorized — with full-path grouping, ["Uncategorized", "Browser"] and ["Uncategorized", "Games"] became separate rows instead of collapsing into one "Uncategorized" bucket.

Fix

Revert parseCategories() to group by $category[0] only, so every "Uncategorized > *" subcategory rolls back into a single "Uncategorized" row.

Tests

Updates CategoryTimeWidgetUpdaterTest to assert the top-level rollup and adds a regression test (parseCategories_collapsesUncategorizedSubcategories) for the inflated-uncategorized fix.

Verified locally: ./gradlew :mobile:testDebugUnitTest --tests 'net.activitywatch.android.widget.*' — 7/7 pass.

Not in this PR

The original per-category discrepancy that motivated #231 needs separate investigation — the full-path change was the wrong fix for it.

Closes #142

[greptile-apps]

Greptile Summary

Reverts widget category grouping from full paths to top-level categories, restoring the compact rollup behavior and consolidating uncategorized subcategories.

• Aggregates category durations using $category[0].
• Updates widget parser tests for top-level rollups.
• Adds regression coverage for collapsing Uncategorized subcategories.

Confidence Score: 5/5

The PR appears safe to merge, with the restored top-level aggregation remaining consistent across the widget’s downstream consumers.

The changed parser preserves total duration while merging rows by top-level category, and the widget’s sorting, chart, colors, and displayed totals all consume that aggregated list consistently.

Important Files Changed

Filename	Overview
mobile/src/main/java/net/activitywatch/android/widget/CategoryTimeWidgetUpdater.kt	Restores top-level category aggregation; downstream totals, sorting, chart proportions, and row rendering remain consistent with the merged data.
mobile/src/test/java/net/activitywatch/android/widget/CategoryTimeWidgetUpdaterTest.kt	Updates expectations for top-level rollups and adds focused regression coverage for uncategorized subcategory consolidation.

_{Reviews (1): Last reviewed commit: "fix(widget): revert category grouping to..." | Re-trigger Greptile}

[TimeToBuildBob]

CI-green and mergeable (Greptile 5/5) — waiting only on a maintainer click.

This PR is ready to merge, but the bot has pull-only access to this repo and can't self-merge — surfacing it here so it isn't lost. The monitoring loop will stop re-flagging it now that this note is posted.