Document deprecation of Language.SCRIPT

[anukalp2804]

Summary

Improves documentation for the deprecated Language.SCRIPT constant.

Motivation

Language.SCRIPT is deprecated but lacked structured deprecation metadata.
This change clarifies the rationale, adds since information, and documents
the recommended replacement.

Changes

• Added deprecation rationale to Javadoc
• Added @Deprecated(since = "4.0.0-alpha", forRemoval = false)
• No behavioral or compatibility changes

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Note: This change is documentation-only and does not affect runtime behavior.

[anukalp2804]

Gentle ping 🙂
Just checking whether this PR needs anything further from my side.
Happy to update it if needed. Thanks!