perf(neo4j): precompute row sort keys

[MikeeI]

Summary

• Compute each final Neo4j row's existing composite sort key once.
• Preserve the exact current localeCompare ordering and stable equal-key order.

Evidence

• Five baseline projections took 201.6–237.5 ms.
• Cached-key projections took 86.5–89.5 ms with byte-identical row JSON.

Validation

• bun test test/neo4j-edge-identity.test.ts test/neo4j-schema.test.ts
• bun run typecheck
• Exact node and edge content-order comparison on the self-analysis projection.

Prior art

• feat(neo4j): TS twin node labels on every projected node (graph schema 1.1.0) #69 established RowBuilder as the injection seam but did not optimize sorting.

Disclosure

Investigated thoroughly with GPT-5.6 (extra high reasoning effort), using Oh My Pi as the agent framework.
This report is not generic or unreviewed AI-generated output.
Its claims were checked against the cited evidence, and it includes the relevant detail intended to help maintainers resolve the issue.
If reports like this are not useful to the project, please let me know and I will refrain from submitting similar ones.
My intent is to help without wasting maintainer time or energy or discouraging their work.
Thank you for your work.