Feature: Dynamically add new language dataset to existing trie

[master-wayne7]

Currently, languages are loaded during initialization using SafeTextFilter.init().

Goal:

• Allow adding a new language at runtime without rebuilding the entire trie

Example:
SafeTextFilter.addLanguage(Language.spanish);

Expected Behavior:

• Merge new dataset into existing trie
• Avoid full reinitialization
• Maintain performance

This will improve flexibility for apps that dynamically switch or load languages.