fix(cli): render structured log messages

[alongubkin]

Summary

• render the human message from structured tracing records stored as JSON strings
• retain the complete source hit in the stable raw field
• leave generic JSON messages untouched

Testing

• cargo test -p alien-cli commands::logs::tests

Linear: ALIEN-569

[greptile-apps]

Greptile Summary

The PR narrows structured tracing-record detection so ordinary JSON matching the previously reported shape remains intact.

• Requires a string target alongside timestamp, level, and fields.message before extracting the human-readable message.
• Preserves the complete source hit in raw.
• Adds tests for tracing extraction and generic-JSON fallback.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains.

Important Files Changed

Filename	Overview
crates/alien-cli/src/commands/logs.rs	Adds a stricter tracing JSON classifier and regression coverage, resolving the previously reported generic-JSON case without an eligible new blocking finding.

_{Reviews (2): Last reviewed commit: "fix(cli): require tracing record target" | Re-trigger Greptile}

[alongubkin]

Verified the final behavior and review fixes:

• recognized tracing records render a readable message
• generic JSON remains unchanged
• complete source data remains available
• focused regression tests pass
• Greptile completed at 5/5 with no blocking findings

Ready to merge.