fix(cli): raise non-zero exit on import errors

[SaitejaKommi]

Summary

This PR ensures the import CLI command fails with a non-zero exit status when import errors occur. The command now raises an explicit Typer exit in the error path, making failure detection reliable for CI and scripts.

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Related issue

• Fixes: CLI Import command should exit non-zero when data import reports errors #377

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Scope

• main.py

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What changed

• In the import command flow:
  • When num_errors > 0:
    • Log the error count
    • Raise explicit exit:

      raise typer.Exit(code=1)

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Why this is correct

• Typer requires raising Exit to terminate with a specific status code
• Ensures CLI behavior aligns with standard Unix conventions
• Enables reliable failure detection in CI and automation workflows

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Testing Done

• Backend unit tests: passed
• Backend integration tests: passed (with expected xfailed cases)
• Frontend test suite: passed