Drop support for raw_dict initialization

[willis89pr]

🧪 Investigate test_cli.py Use of Raw Dict SBOM Input

Currently, test_cli.py constructs a malformed SBOM using a raw dictionary:

https://github.com/LLNL/Surfactant/blob/10e89bc03a6f71caef8638bd2d51de36a01d5ba1/tests/cmd/test_cli.py#L48-L75

bad_sbom = SBOM({...})

This raw dict form requires fallback parsing logic inside the SBOM.__post_init__ method:
https://github.com/LLNL/Surfactant/blob/10e89bc03a6f71caef8638bd2d51de36a01d5ba1/surfactant/sbomtypes/_sbom.py#L67-L122

That code attempts to detect if the input was a dict by checking:

if isinstance(self.systems, dict) and not self.hardware and not self.software:

It then zeroes out all the default containers and performs a custom rehydration of systems, hardware, software, relationships, etc. This logic was introduced in PR #433 and exists solely to make the bad_sbom test pass.

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❌ Why This Is Problematic

• Unclear contract: Constructing SBOM(raw_dict) implies support for a dict constructor signature that isn't advertised or robust.
• Tight coupling: Unit test behavior now relies on internal implementation quirks (__post_init__ behavior).
• Rehydration risk: The fallback code path only applies if hardware, software, etc. are unset, making it brittle and potentially dangerous if partial containers exist.
• Non-portable tests: This usage breaks when stricter schema validation or type enforcement is added to SBOM.

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✅ Suggested Fix

• Refactor test_cli.py to avoid creating SBOMs via dict fallback. Instead, construct malformed SBOMs via:

  • SBOM.from_json(bad_json) for malformed input
  • SBOM(software=[Software(..., extra_field=...)]) using valid constructors with bad fields

• Remove or isolate the fallback rehydration block in SBOM.__post_init__ if it’s no longer required outside tests.

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🔧 Acceptance Criteria

• bad_sbom is constructed using a valid constructor or deserializer
• Tests still validate failure handling for malformed input
• The dict rehydration path in __post_init__ (_sbom.py#L67-L122) is removed entirely

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