fix(tables): reject a non-leading sign so dates don't parse as amounts

Found by Cursor Bugbot. `parseCurrencyInput` dropped every `-` as decoration,
so an ISO date's hyphens vanished and its digit groups joined: `2024-01-01`
read as 20240101. With the gate now sharing the write path's parser, a
date → currency conversion reported zero incompatible rows and silently
turned every cell into a huge number.

A sign is only meaningful at the front; an interior one means the string is
not a single amount. Leading signs, accounting parentheses, symbols, ISO
codes, grouping separators, and exponent form all still parse — covered by
the existing cases plus new ones, verified to fail without the fix.

Author: waleedlatif1

apps/sim/lib/table/__tests__/currency.test.ts

@@ -89,6 +89,20 @@ describe('parseCurrencyInput', () => {
     expect(parseCurrencyInput(formatCurrencyForInput(1e21))).toBe(1e21)
   })
 
+  it('rejects a sign that is not leading, so dates do not read as amounts', () => {
+    // A date column converting to currency previously turned `2024-01-01` into
+    // 20240101 — the hyphens were dropped as decoration and the digit groups
+    // joined. Every cell in the column would have been silently corrupted.
+    expect(parseCurrencyInput('2024-01-01')).toBeNull()
+    expect(parseCurrencyInput('2024-01-01T10:30:00Z')).toBeNull()
+    expect(parseCurrencyInput('1-2-3')).toBeNull()
+    expect(parseCurrencyInput('12--3')).toBeNull()
+    // A leading sign is still a sign.
+    expect(parseCurrencyInput('-12')).toBe(-12)
+    expect(parseCurrencyInput('+12')).toBe(12)
+    expect(parseCurrencyInput('-$12.50')).toBe(-12.5)
+  })
+
   it('rejects values carrying no amount', () => {
     expect(parseCurrencyInput('')).toBeNull()
     expect(parseCurrencyInput('   ')).toBeNull()

apps/sim/lib/table/currency.ts

@@ -147,8 +147,15 @@ export function parseCurrencyInput(raw: unknown): number | null {
   const stripped = body.replace(/[^\d.,\-+]/g, '')
   if (!/\d/.test(stripped)) return null
 
-  const negative = parenthesized !== null || stripped.startsWith('-')
-  const digitsAndSeps = stripped.replace(/[+-]/g, '')
+  // A sign is only meaningful at the front. An interior one means this is not a
+  // single amount, and dropping it would join unrelated digit groups — an ISO
+  // date (`2024-01-01`) would otherwise read as 20240101, so converting a date
+  // column to currency would silently turn every cell into a huge number.
+  const signed = /^[+-]/.test(stripped)
+  const digitsAndSeps = signed ? stripped.slice(1) : stripped
+  if (/[+-]/.test(digitsAndSeps)) return null
+
+  const negative = parenthesized !== null || (signed && stripped.startsWith('-'))
 
   const lastComma = digitsAndSeps.lastIndexOf(',')
   const lastDot = digitsAndSeps.lastIndexOf('.')