#1355 Add LinguaMesh

A single, relevant library entry following this list's contribution format. LinguaMesh implements Java text tokenization and language-specific analysis providers; this entry belongs in Java NLP libraries.

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Summary by cubic

Adds LinguaMesh to the Java NLP libraries section of README_SOURCE.md.

The listing describes the library's modular text-tokenization API and its selectable language-analysis providers, matching the contribution format of existing entries.