feat(accounts): highlight negative disk usage with recalculate hint

src/lib/durationFormat.test.ts

@@ -68,6 +68,15 @@ describe('bytesToHuman', () => {
   it('should convert 1099511627776 bytes to 1 TB', () => {
     expect(bytesToHuman(1099511627776)).toEqual({ value: 1, unit: 'TB' });
   });
+
+  it('should format negative byte counts with a minus sign', () => {
+    expect(bytesToHuman(-9515272)).toEqual({ value: -9.07, unit: 'MB' });
+  });
+
+  it('should treat non-finite byte counts as empty usage', () => {
+    expect(bytesToHuman(Number.NaN)).toEqual({ value: 0, unit: 'B' });
+    expect(bytesToHuman(Number.POSITIVE_INFINITY)).toEqual({ value: 0, unit: 'B' });
+  });
 });
 
 describe('humanToBytes', () => {
@@ -108,6 +117,10 @@ describe('formatSize', () => {
   it('should format large values in TB', () => {
     expect(formatSize(1099511627776)).toBe('1 TB');
   });
+
+  it('should format negative byte counts with a minus sign', () => {
+    expect(formatSize(-9515272)).toBe('-9.07 MB');
+  });
 });
 
 describe('msToHuman', () => {

src/lib/durationFormat.ts

@@ -15,15 +15,18 @@ const SIZE_FACTORS: Record<string, number> = {
 };
 
 export function bytesToHuman(bytes: number): { value: number; unit: string } {
-  if (bytes === 0) return { value: 0, unit: 'B' };
+  if (!Number.isFinite(bytes) || bytes === 0) return { value: 0, unit: 'B' };
+
+  const sign = bytes < 0 ? -1 : 1;
+  const abs = Math.abs(bytes);
 
   for (let i = SIZE_UNITS.length - 1; i >= 0; i--) {
     const unit = SIZE_UNITS[i];
     const factor = SIZE_FACTORS[unit];
-    const v = bytes / factor;
+    const v = abs / factor;
     if (v >= 1) {
       const rounded = Math.round(v * 100) / 100;
-      return { value: rounded, unit };
+      return { value: sign * rounded, unit };
     }
   }