Fix npm install startup failure without ioredis

[zhengkezhou1]

Summary

• import Effect Node services through their focused subpath exports
• avoid evaluating the root platform barrel and its Redis integration during extension startup

Verification

• npm run format:check
• npm run check
• npm test (591 Node tests and 29 Vitest tests)
• packed and installed the package with --legacy-peer-deps; confirmed ioredis is absent
• installed that isolated package with pi install --local and launched Pi 0.82.1; all OpenPI extensions, including file-search and git-info, loaded successfully

Closes #2

[tt-a1i]

Review

P0 — correctness / architecture

No actionable findings. The focused NodeServices / NodeHttpClient subpath imports fix the root cause without adding the unused optional Redis peer.

P1 — tests / package contract

No actionable findings. CI passes on Node 22.19 and 24, and the runtime import guard prevents the root barrel from returning.

Independent clean-install verification:

• packed this branch and installed it with --legacy-peer-deps; ioredis remained absent
• pi --offline --mode rpc --no-extensions --extension <file-search> --extension <git-info> exits 0
• the published 0.1.1 tarball under the same conditions exits 1 with the reported Cannot find module 'ioredis' errors for both extensions\n- local gates: format check, typecheck, 592 Node tests, 29 Vitest tests, git diff --check, and package allowlist inspection all passed\n\nThis is ready to merge. I did not approve because final approval remains a maintainer decision.

[tt-a1i]

Follow-up review correction

The runtime fix remains correct and the independent clean-install E2E passed. One P1 test gap remains: extensions/setup/package-contract.test.ts only scans source with a regex, so CI does not itself prove startup in an installation where ioredis is absent; it can also false-match comments/strings and miss alternate root loads.

Recommended before merge: add an isolated packed-install subprocess smoke that installs with optional peers omitted and starts both file-search and git-info. The source guard may remain as a fast supplemental check. This does not block correctness of the current fix, but it would lock down the exact published-package regression.