Add comprehensive unit tests for `js/ui/dm/zapHelpers.js` in `tests/ui/dm/zapHelpers.test.mjs`.
- Covers `formatZapAmount` for standard and compact notation.
- Covers `aggregateZapTotals` for aggregation logic and edge cases.
- Covers `normalizeZapReceipt` for input normalization.
- Ensures robust handling of invalid inputs (NaN, null, etc.).
Signed-off-by: Jules <[email protected]>
Co-authored-by: PR0M3TH3AN <[email protected]>