[Bug] Inconsistent skill name length limit between init_skill.py and quick_validate.py

## Description

There is an inconsistency in the skill name length limit between the init script and validation script.

### According to the Spec

Per the [Agent Skills Specification](链接到规范网页), the `name` field requirements are:

> **name field**
> The required name field:
> - Must be 1-64 characters
> - May only contain unicode lowercase alphanumeric characters and hyphens (a-z and -)
> - Must not start or end with -
> - Must not contain consecutive hyphens (--)
> - Must match the parent directory name

### Current Behavior

| File | Location | Description |
|------|----------|-------------|
| `skills/skill-creator/scripts/init_skill.py` | Line 279 | Help message incorrectly states `" - Max 40 characters"` |
| `skills/skill-creator/scripts/quick_validate.py` | Line 70 | Correctly validates `if len(name) > 64:` per spec |

## Impact

Users running `init_skill.py` see a help message indicating 40-character max, which contradicts:
1. The official spec (1-64 characters)
2. The actual validation logic in `quick_validate.py` (64 characters)

This inconsistency may confuse users when creating new skills.

## Suggested Fix

Update the help message in `init_skill.py` to match the spec (64 characters).