Add ToolsHref to Code Analysis section

[toolshref-tools]

Hello! I'd like to contribute a useful developer utility to the list.

Resource Name: ToolsHref Link: https://toolshref.com Description: A browser-based suite of developer tools, including a Java Code Analyzer for static analysis and a JSON-to-Mermaid generator for visualizing data structures, Date and time code generators for java, JavaScript, etc.

Why it fits: It provides a free, no-login alternative for quick static analysis and data visualization, similar to other utilities already listed here.

I have checked the contribution guidelines and ensured the link is valid. Thanks for maintaining this awesome list!