Preserve number padding in increment/decrement actions

[trillium]

Overview

Preserve leading zeros when incrementing or decrementing a number.

Before:

# increment this
01 -> 2

After:

# increment this
01 -> 02

• Add hasLeadingZeros() helper to detect numbers with leading zeros
• Add formatNumber() function to preserve original number formatting (leading zeros and decimal places)
• Update updateInteger() and updateFloat() to return formatted strings instead of raw numbers
• Preserve formatting for numbers like 007 → 008, 3.0 → 4.0, and 004.60 → 005.60
• Add comprehensive test fixtures for increment/decrement scenarios