impr(quotes): add more code_java quotes (@theFaustus) (monkeytypegame#7100)

### Description

This PR introduces a curated set of Java quotes that combine typing
practice with real programming content.
The snippets include examples from common algorithms, OOP patterns,
functional and concurrent programming, and recent Java features like
records, sealed classes, and switch expressions.

Goal: help users improve typing speed and accuracy while reinforcing
Java syntax and idioms in a practical way.

### Checks

- [x] Adding quotes?
- [x] Make sure to include translations for the quotes in the
description (or another comment) so we can verify their content.

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Co-authored-by: Ion Pascari <[email protected]>

Author: theFaustus