perf(cache): skip projects on complete warm L1 hits

[MikeeI]

Summary

• Classify complete Level-1 cache reuse before constructing compiler projects.
• Preserve cold, partial, invalidated, and Levels 2–4 behavior.

Evidence

• Five current warm Level-1 runs took 94.1–100.7 ms with a 98.7 ms median.
• Project-free runs took 53.6–62.1 ms with a 56.7 ms median and byte-identical output.

Validation

• bun test test/l1-body-cache-shape.test.ts test/multi-tsconfig.test.ts test/schema-v2.test.ts
• bun run typecheck
• Five exact warm Level-1 application-output comparisons.

Prior art

• Scaling L1-L4 past vscode: three memory ceilings and a sequenced path #112 proposes broader incremental reuse and bounded Project residency but not this Level-1 fast path.

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.