feat: Add initialization check and error for already initialized cont…

[Aonlike]

Closes #68

PR Documentation

Summary

Describe what this pull request changes and why.

Related Issue

• Fixes # (if applicable)
• Related to # (if applicable)

Changes

• Bullet point key changes made in this PR.
• Include any new tests or documentation updates.

Testing

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• cargo test
• specific test cases or scenarios run

Checklist

• PR is focused and scoped
• Tests added or existing tests updated
• Code compiles cleanly
• Documentation updated when needed
• No unrelated changes included

Notes

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