A flat entity's gate room is neither committed by state commit nor migratable to folder form

[clkao]

Flat tickets can now retain prepared gates and advisory rounds across clones without breaking historical room references.

What changed

• Store new gate and round rooms under canonical @review/... paths.
• Preserve historical flat, folder, and Git-root reference semantics.
• Enforce Artifact containment and malformed reserved-reference refusal.
• Add fresh-clone, replay, and byte-clean refusal coverage.

Evidence

• Repository suites: 2/2 passed (go test ./... and race).
• Focused gates/status/CLI suites: 3/3 passed.

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