fix(sort): explorer-like ordering for leading-zero prefixes

[AlexAndBear]

Summary

Fixes sorting for files and folders with leading-zero prefixes (e.g., 00000_*, 0000_*, 00_*, 0_*) to match Windows Explorer behavior.

Problem

The web client uses natural sorting with Intl.Collator and numeric: true, which treats different numbers of leading zeros as the same numeric value (0). This breaks intentional ordering schemes where users rely on distinct zero prefixes to organize their files.

Example: 00000_Important, 0000_Archive, 00_Projects, 0_Other were all treated as starting with 0 and sorted only by the text after the prefix.

Solution

Added special handling in useSort.ts for names with leading-zero prefixes:

1. Detection: Regex ^(0+)(?!\d)(.*)$ identifies pure zero prefixes
2. Comparison priority:
   • Compare by prefix length (more zeros → higher priority)
   • Then compare suffixes using natural sorting
   • Use full name as tie-breaker
3. Fallback: Names without zero prefixes use existing natural sorting

Examples

With fix (ascending):

• 00000_ITEM_ALPHA
• 0000_BLOCK_ALPHA
• 00_SET_ALPHA
• 0_NODE_ALPHA

Regular names still work naturally:

• file1, file01, file001, file2, file02, ...

What Stays the Same

• Folder/file grouping unchanged
• Non-name sort fields unchanged
• Extension handling unchanged

Testing

• Extended useSort.spec.ts with anonymized zero-prefix datasets
• Verified ascending/descending order for both files and folders
• Existing natural sorting tests still pass

Closes #2993