Refactor ci-tools provider command and HTTP boundaries to Effect platform services

Summary

Follow-up from the ci-tools deploy-preview migration review: Netlify/Vercel provider adapters should move their command execution and HTTP fetch boundaries onto first-class Effect platform services instead of ad hoc spawnSync / globalThis.fetch wrappers.

Motivation

The current migration centralizes deploy semantics in ci-tools and has full fake/live E2E coverage, but some provider internals still use pragmatic Node boundaries. Moving those boundaries to @effect/platform would better align with the repo's Effect conventions and make command start failures, HTTP client layers, interruption, redaction, and observability more principled.

Scope

• Replace provider command runners with @effect/platform Command usage where practical.
• Replace provider lookup fetches with HttpClient layers and explicit bearer-token request construction.
• Preserve existing workflow-report failure records and token redaction behavior.
• Keep the existing fake-provider and live E2E contracts passing.

Non-goals

• Do not change deploy task semantics or provider alias behavior.
• Do not commit provider identifiers or secret values.

Verification

• devenv tasks run test:ci-tools --no-tui
• devenv tasks run ts:check:strict --no-tui
• devenv tasks run lint:check --no-tui
• relevant live E2E only when credentials are available

Start in the ci-tools provider adapters and trace the existing command runners and provider lookup fetches, then review the fake-provider and live E2E contracts. The work is done when @effect/platform services replace the ad hoc boundaries while workflow-report failures, token redaction, provider aliases, and deploy semantics remain unchanged; run the listed ci-tools, strict TypeScript, and lint checks.