The by-category report combobox (`/reports/category`) was showing its full
category list with scrambled indentation — parents from one sub-tree
interleaved with children from another. Root cause: `getAllCategoriesWithCounts`
returns rows via `ORDER BY sort_order, name`, which is a *global* sort; two
different roots with sort_order=1 would be followed by their respective
children in the same bucket, mixing depths together.
Add a pure `sortHierarchical(categories, resolveName)` helper in
`CategoryCombobox.tsx` that rebuilds the display order as a DFS walk of the
tree: each parent is emitted immediately followed by its descendants, with
siblings within a group sorted by `sort_order` then localized display name.
Orphans (parent filtered out or missing) are appended at the end so nothing
disappears. The helper runs client-side inside the combobox's `useMemo`, so
the fix is scoped to this component and doesn't affect other consumers of
`getAllCategoriesWithCounts`. Filtering on the input query remains unchanged.
Covered by 7 unit tests on the helper (empty list, single root, the exact
bug-reproducing scrambled case, sort_order + name tiebreak, 3-level
hierarchy, orphans, idempotence).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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