Preserve failure identity during minimization

[Taz33m]

Summary

• preserve operational status and divergence category across trace reduction
• prevent a specific classified failure from broadening, while allowing causal-noise removal to narrow generic execution drift to queue-priority drift
• reuse that identity rule across campaign minimization and exact reproduction checks
• add regressions for both directions of the classification rule

Verification

• full pytest suite passed
• Black, Flake8, mypy, Bandit, and compileall passed
• focused conformance, campaign, exit-code, and artifact-schema tests passed
• exact 15,739-event Flash handoff minimization restores the canonical four-event fixture byte-for-byte
• historical issue-88 campaign and exact reproduction remain unchanged

[cubic-dev-ai]

All reported issues were addressed across 7 files

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