fix(sql): read historical empty file content

[samuelstroschein]

Summary

• distinguish actual historical plugin ownership from ordinary blobless files
• load the durable plugin-owner row alongside historical file content state
• keep rejecting genuinely plugin-owned files whose durable materialization is missing
• add regressions for raw empty, owned blobless, and materialized plugin files

Why

An empty tracked file has a descriptor but intentionally no blob reference. Point-in-time file reads treated every such descriptor as potentially plugin-owned and returned historical plugin-owned file is missing its durable materialization. This broke LixRay review-mode previews for empty files such as a newly created CSV.

Complexity

This changes only cold lix_state_at('lix_file', ...) reads that project content. They perform one additional indexed owner-row scan. Full historical reads remain linear in retained file/blob/directory/owner rows; exact-ID reads remain point-scoped. Live/HOT reads add no I/O or plugin execution.

Public surface

No Rust, JS, or SQL API/surface changes.

Local verification

• cargo nextest run -p lix --features all-simulations — 3,451 passed
• cargo test -p lix --doc — 10 passed
• two independent agent reviews — approved, no findings

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-01T06:09:39.368665Z	d4376b3	PR opened

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