fix: low-contrast secondary text color in global theme token

[Nam0101]

Description

The LESS variable text-color-secondary is set to #c0c0ca, which has poor contrast on light backgrounds (commonly white in Ant Design layouts). Because this token is used globally, secondary labels, helper text, and metadata can become hard to read for low-vision users and may fail WCAG AA contrast requirements.

Severity: medium
File: amoro-web/vite.config.ts

Expected Behavior

The code should handle this case properly to avoid unexpected errors or degraded quality.