Expose encrypted stream size helper

[m-rosinsky]

Summary

• add an overflow-safe helper that predicts secretstream ciphertext size
• expose it consistently in Rust, JavaScript/Node, Python, Go, JVM, and .NET
• add boundary tests, API docs, generated native interfaces, and refreshed Go prebuilts

Validation

• make ci
• JavaScript/WASM tests
• Python tests (61 passed)
• Go tests
• JVM tests (59 passed)
• .NET tests (72 passed)

[github-actions]

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1 out of 2 committers have signed the CLA.

✅ m-rosinsky
❌ github-actions[bot]
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