fix(18-07): money accepts trailing zeros beyond the field scale

A scale-2 money field over a four-decimal column (the documented fee
example) was served "12.5000" and answered money.too_precise when the
untouched value was saved back. Trailing zeros carry no precision, so the
server check and the SPA parser count only significant fraction digits;
the value still reaches the column unchanged, never rounded or truncated.

- cabana validateMoneyValue and admin parseMoneyInput trim trailing zeros
  before the scale comparison
- forms docs and cabana README name the rule; embedded dist rebuilt
- MoneyField spec asserts 12.5000 at scale 2 is accepted, 12.5010 refused

admin/tests/form/MoneyField.test.ts

@@ -65,6 +65,9 @@ describe('money helpers', () => {
     expect(parseMoneyInput('', 4)).toEqual({ value: null, error: null })
     expect(parseMoneyInput('   ', 4)).toEqual({ value: null, error: null })
     expect(parseMoneyInput('12.34567', 4)).toEqual({ value: null, error: 'too_precise' })
+    // Trailing zeros beyond the scale carry no precision: kept, accepted.
+    expect(parseMoneyInput('12.5000', 2)).toEqual({ value: '12.5000', error: null })
+    expect(parseMoneyInput('12.5010', 2)).toEqual({ value: null, error: 'too_precise' })
     expect(parseMoneyInput('1.234,56', 4)).toEqual({ value: null, error: 'invalid' })
     expect(parseMoneyInput('12a', 4)).toEqual({ value: null, error: 'invalid' })
     expect(parseMoneyInput('1e3', 4)).toEqual({ value: null, error: 'invalid' })