perf: cache review prompt assets

[stainlu]

Summary

• cache the static review prompt and decision schema lazily within each ClawSweeper process
• reuse cached bytes for review policy hashing, item prompt rendering, and the check command
• keep the schema path passed to Codex stable

Validation

• pnpm run build
• node --test test/clawsweeper.test.ts
• pnpm run lint:src
• pnpm run lint:scripts
• pnpm run format:check
• git diff --check

[steipete]

This caching change is useful, but it needs a rebase against current main. The prompt/schema helper area has moved with the review telemetry work, so please adapt this to the current helper names instead of reintroducing duplicate file reads or parallel cache helpers.

After rebase, please rerun pnpm run check. The behavior to preserve is simple per-process caching of the static review prompt and decision schema while keeping the Codex --output-schema path unchanged.

[stainlu]

Rebased on current main and reran pnpm run check under Node 24. This now caches the current reviewPromptTemplate() / reviewDecisionSchemaText() helpers and keeps the Codex --output-schema path unchanged.

[steipete]

Landed manually on main as fb9c2f32fd (perf: cache review prompt assets) after resolving the current CHANGELOG.md, src/clawsweeper.ts, and test import conflicts. Kept REVIEW_POLICY_VERSION at v14, preserved the stable Codex --output-schema path, and kept the tracked-file regression. Full local pnpm run check passed before push. Thanks @stainlu.